JS console.gotoxy() and the GOTOXY @-code now work with PETSCII terminals
(homes the cursor then moves down and right the appropriate number of rows
and columns). Bummer I didn't think of this method sooner.

Use cursor-right movement rather than spaces for left-margin.
Don't do the clear-to-EOL thing added in previous commit.

"width" argument (in columns), defaults the user's current screen column-width
but you can now over-ride this value when an additional/optional argument.
Also, center() now clears-to-EOL before sending the CRLF to the terminal.
Hopefully this doesn't mess up anyone's existing use of center().

it's a CP437 character (e.g. inadvertently included in a UTF-8 encoded text)
and display as such.

when "extra raw" output is needed.
Use putcom() and comprintf() instead of rputs() and rprintf() for ANSI escape
sequences. This doesn't actually fix any problem, but since rputs() is
"less raw" than it used to be, let's use direct-output routines instead, for
ANSI output.

line counter was never cleared (upon rputs() of "\n") and the current attribute
was not saved when a new line was being buffered.
This applies to JS console.write() as well since it uses rputs().

- new @-code BPS:x (where x is 0/unlimited, 300, 600, 1200, 2400, ... 115200)
- new JS property: console.output_rate
So you can have mutliple output rate changes in a single file by using multiple
BPS @-codes.
Hopefully this doesn't do weird things with non-compliant terminals.

now accept an optional "count" argument (default: 1).
JS console.backspace() and carrage_return() methods now accept an optional
"count" argumnet (default: 1).

- bstrlen() moved to sbbs_t, accepts an option pmode argument so it can account
  for UTF-8 encoded strings correctly
- JS console.strlen() now accepts an optional pmode argument (e.g. P_UTF8)
- Renamed sbbs_t::utf8_to_cp437 to sbbs_t::print_utf8_as_cp437
- Create/use msghdr_hfield() to perform UTF-8->CP437 conversions as needed for
  printing/copying UTF-8 encoded message header fields.
- Defined XTRN_UTF8 misc setting flag. If a message editor does *not* have this
  flag, it is assumed to *not* support UTF-8. Will likely use this for UTF-8
  doors as some point too (none known to exist, yet).

auto-limiting the length of printed lines to avoid  terminal line wrapping.
putmsg() already supported this pmode flag.

- Export all FIDOCTRL (other FTN kludge lines) to the QWK HEADERS.DAT file.
  These should already be imported if they exist, but were never added during
  export, so untested/new behavior. The control paragraph (kludge line) of
  specific interest here is the "CHRS" (charset) kludge we need for UTF-8.

- Don't use the QWK "newline" character (0xE3) when the message is UTF-8.
  Use bare-LF's instead. This is pretty untested at this point as I will need
  another QWKnet board to post or receive UTF-8 encoded messages to test,
  getting the code into CVS is the first step. At least for now, there's no
  opt-in/out for this behavior. If your BBS has UTF-8 encoded messages, some
  QWK nodes or offline readers may have trouble with packets which include
  those messages. Or they may work fine (but likely display garbage CP437
  chars in-place of the proper Unicode codepoint glyph).

- The beginning of UTF-8 input support in getstr() - which needs more work,
  particularly around character and word deletion and insertion.
- The internal message editor now supports UTF-8 messages and kind of somewhat
  supports inputting UTF-8 characters in message text.

New put/print text flag: P_AUTO_UTF8 which can auto-detect UTF8 strings and
do the "right thing" for the user's terminal. New associated sbbs_t method:
auto_utf8() which automatically sets P_UTF8 for any stirng that begins with
a UTF-8 BOM (ZWNBSP). Else, if the P_AUTO_UTF8 mode flag is set, then
it checks to see if the string contains invalid US-ASCII chars but valid UTF-8
sequences and then sets P_UTF8 accordingly. Used by putmsg() and bputs().

There's a new permuation of bprintf() which accepts a mode argument
(i.e. for P_UTF8) and passes it on to the new mode-capable bputs().

string (multiple) CP437 fallback chars, for when a single CP437 char won't
suffice.

problems loading font data in SyncTERM over Telnet.

terminal "type" string (ANSI, RIP, PETSCII, or DUMB).
Expose this value in JS via the new console.type read-only property.
The TERM @-code now expands to this string rather than the (often
client-supplied) sbbs_t.terminal string value.

Create a sbbs_t method: wide(), which displays a string using "fullwidth"
Unicode characters, when possible, otherwise, double-spaced.
Exposed in JS via console.wide() and a new @-code: WIDE:<string>

with UNICODE_*

@U+<codepoint-in-hex>@ - automatic CP437 fallback char, if available
@U+<codepoint-in-hex|cp437char-in-hex>, specify CP437 fallback char
@U+<codepoint-in-hex!cp437char-in-hex>, specify CP437 fallback char
(used if no automatic fallback mapping is available)

Since not *everything* that #include's sbbs.h needs the PETSCII defs,
remove it from sbbs.h and just #include petdefs.h where we need it.
The catch-all header file is a problematic organizational design and we are
moving away from that.

New function (derived from sbbs_t::utf8_to_cp437()): unicode_to_cp437()
New utf8 functions: utf8_replace_chars(), utf8_str_is_valid().
utf8_getc() enhancement: val arg may be NULL (for length/validation uses).

Convert quoted UTF-8 message text to CP437 when terminal is not UTF8.

Set Fido CHRS: UTF-8 header field when posted message is UTF-8.

for both US-ASCII (non-CP437) terminals and UTF-8 terminals.

notice.

with ZWNBSP/BOM UTF-8 sequence) and messages (with the "CHRS: UTF-8"
FTN control paragra or MIME "charset=utf-8" parts).
Not all UNICODE codepoints are supported (obviously).
Tested with various files from ftp://columbia.edu/kermit/charsets/
(e.g. test.utf8, utf8-boxes.txt)

translation from CP437 -> UTF-8 and only when using high-level text output
functions - so the output from native/DOS doors and scripts that use low-level
output methods won't be translated.
UTF-8 is auto-detected (only) at this time during answer (before login) by
sending a ZWNBSP and checking (via ANSI) if the cursor position moved - an
idea "borrowed" from Ozz Nixon (aka SqZ).

This commit requires the new "encode" library (src/encode), so you may need
to perform a cvs checkout to get that module!

- for PETSCII, this is automatic and you don't lose blink, but you do lose
  colored foreground when enabling a bright background ("reverse video")
- for ANSI, this mode is typically referred to as "iCE colors" and disables
  blinking-text support
- Ctrl-AE (^AE) is the new attribute code to enable bright-background
  (will have no effect on ANSI terminals that are not iCE color enabled)
  "E" is now valid in the ctrl/attr.cfg file and string values for JS
  console.attributes assignments, as well
- Ctrl-AI (^AI) - blink - now does nothing for ANSI/ICE color terminals
  (blinking is not supported in combination with bright-background)
- Using a new/non-standard CGA attribute bit-flag to indicate the selection of
  bright-background colors (BG_BRIGHT, bit 10), separate from BLINK.
  This change required all/most char/uchar attribute representations to be
  converted to int/uint.

New text.dat strings:
- PetTerminalDetected (renamed from PetTermDetected)
- PetTerminalQ
- TerminalAutoDetect
- TerminalColumns
- TerminalRows
- TerminalMonochrome
- TerminalColor
- TerminalIceColor
- IceColorTerminalQ
This also moved the MsgCarbonCopyList definition to the end of the file
for now.

PETSCII reverse-video attribute fix:
When a CR is sent to the terminal, the reverse-video attibute is auto-disabled
so update our "current attribute" (curatr) value to match the remote.

Support new printfile/putmsg mode flag: P_WRAP to force an ungraceful
line-wrap (splitting) to the specified column width. If no column width is
specified (0), then this mode will force an ungraceful wrap before the last
terminal column where some terminals *may* auto-wrap.

JS console.printfile() and printtail() methods now support an optional
"orig_columns" argument, similar to console.putmsg(). Must specify P_WORDWRAP
or P_WRAP for this argument to have any effect.

Much improved terminal-type selection/configuration in the user defaults
menu and abort (^C) at any of the yes/no prompts is now detected/handled much
better (to answers to the prompted questions are not saved to the user
settings).

when set, force a clear-to-end-of-line sequence to be sent to the remote
terminal before sending a carriage-return (CR, '\r') character. This is useful
in scenarios where you want to move/home the cursor and *not* clear the screen
and then display or execute something that assumes clean lines are being
displayed on and thus wouldn'd bother with any clear-to-eol sequences before
line-endings.
Any scripts that enable this mode should disable it upon exit (e.g. using
js.on_exit() to restore the original console status).

will be sending 0x7f (DEL) when the backspace key is struck: SWAP_DELETE
For example, xterm sends 0x7f when backspace and hit and an ANSI escape
sequence when the DEL key is hit.

I don't yet have a way to *enable* this setting.

Also, allow the user's setting of NO_EXASCII to take effect even when
auto-terminal type detection is used (yes, the user's terminal can support
ANSI and *not* CP437).

I noticed that printable ctrl chars (e.g. 0x18 and 0x19) were not causing the
current column position to increment, so that got me looking at this code and
wondering why the LF/FF checking was outside the if(!outchar_esc) condition
and being executed when CON_R_ECHO is off. So now, using a switch statement,
it's cleaner and all the printable ctrl chars move the current column position
correctly.

Oct-14-2018:
It turns out, PabloDraw actually inserts a Ctrl-AZ sequence at the end of .msg
(and presumably Synchronet .asc) files it edits - before the SAUCE record.
This resulted in a printed Ctrl-Z character (arrow pointing right) in most
terminals when viewing text/menu files created or edited with PabloDraw. :-(
So, now Ctrl-AZ (uppercase) will revert to the previous definition:
premature end-of-file (EOF)
and a Ctrl-Az (lowercase) will output a Ctrl-Z (substitute) character.
I'm not a big fan of case-sensitive Ctrl-A codes, but frankly, running out of
chars and I already started this pattern with the Ctrl-AF/f sequences.
Hopefully there's no existing software that is/was putting Ctrl-Az (lowercase)
in files, expecting that to trigger a premature EOF. I certainly was not.

now have their output translated to PETSCII equivalents for PETSCII terminals
(but input is not yet translated).
.seq files are now sent untranslated via printfile() and putmsg() to PETSCII
terminals (using the new P_PETSCII putmsg mode flag).
.seq files (and P_PETSCII mode text printed via putmsg) is now converted
(poorly) from PETSCII to CP437 - this is still a work-in-progress.
Remove the remants of WIP and HTMLterm support from putmsg() and printfile().

don't use the stored user terminal type. This allows the same user (e.g.
the sysop) to be logged onto multiple nodes concurrently with different
terminal types without effecting the other node/session.
Guest sessions were already immune to this problem.

So Omegix recently asked in the Synchronet Discussion group whether or not
a PETSCII (Commodore) terminal could be used to access his Synchronet BBS.
Now, the answer is "Yes". :-)
The major issues addressed:

- detecting a PETSCII terminal, solved by assigning specific (configurable):
  TCP ports to be used for incoming PETSCII connections, by default:
  port 64 is for 40-column PETSCII and port 128 is for 80-column PETSCII,
  but if the terminal sends a Telnet Window Size reply (e.g. SyncTERM), then
  either size terminal should fine on either port.
  The port numbers are configurable in the [BBS] section of your sbbs.ini
  file using the new keys: PET40Port (default value: 64) and PET80Port
  (default value: 128). Having these keys set doesn't make make the terminal
  server listen on that additional port - you'll need to add more
  IP:port combinations to one of Interfaces values, example:
    TelnetInterface=71.95.196.34,71.95.196.34:64,71.95.196.34:128
  And you don't have to use Telnet for the PETSCII connections - you could use
  RLogin or SSH instead (or in addition).

- support for terminal widths < 80 columns:
  This was achieved through a combination of text.dat changes (numerous),
  new Ctrl-A and @-codes and new optional terminal-width-specific menu files
  (e.g. text/menu/main.40col.asc)
  A side effect of these changes is actually better support for terminals
  *wider* than 80 columns as well!

- support for terminals that don't expand tabs to spaces (e.g. PETSCII):
  The terminal server now handles tab expansion with a run-time settable
  tab-size (default size: 8)

- conditional access based on PETSCII (or small) terminal use (or not):
  + New PETSCII ARS keyword (boolean)
  + New COLS and ROWS ARS keywords (for terminal width and height requirements)
  + New TERM (string) ARS keyword

New @-codes:
  - WORDWRAP, when placed at the top of a file, enables auto-wordwrap for
              lines longer than the terminal width
  - CENTER, the text following before an end of line will be displayed centered
            on the terminal (whatever the width, in columns)
  - CLEAR, like CLS, except it ignores (doesn't display) a CRLF that follows
  - COLS, current number of terminal columns (width)
  - ROWS, current number of terminal rows (height)
  - TERM, the auto-detected or reported terminal type (e.g. ANSI, TTY, etc.)
  - SYSONLY, toggles "echo" (display) off/back-on for non-sysops
            similar to the Ctrl-A( and ) codes, but more convenient to use
            (and PabloDraw won't strip the @-code from the file like it does
             with Ctrl-A codes it doesn't support)

New Ctrl-A codes:
  - \ conditional new-line/continuation when the terminal width is < 80 cols
      prints the new text.dat string LongLineContinuationPrefix

yesno() will now return true if passed a blank string.
noyes() will now return false if passed a blank string.
getstr()'s input length limiting based on terminal width is more broadly
           applied now (not just when using the K_LINE mode flag).

New JS bbs object method: menu_exists(<base_filename>) returns Boolean
New JS console object property: tabstop (Number)
New JS console object methods: getbyte() and putbyte() to recv/send raw byte
    value with (very little) interpretation/intervention by the terminal server
New JS console object method: creturn() - performs a carriage return
    (or equivalent)
New JS (and C) printfile() mode flag: P_TRUNCATE, causes long lines to be
    truncated, rather than displaying causing a line-wrap.

New text.dat strings:
  - NoAccessTerminal (for ARS check failures)
  - LongLineContinuationPrefix (for breaking long lines for 40col terminals)
  - Scanning (replaces a previously hard-coded "Scanning" string)
  - Done (replaces a previusly hard-coded "Done")
  - Scanned  (when finished scannning, clears the progress bar)

was so pervasive. I hope I don't regret changing this. Ctrl-AZ == Ctrl-Z just
"feels right" while Ctrl-AZ == EOF feels stoopid. :-/

('?' from the Reading Messages prompt) would not fully display because
it contains a Ctrl-Z character (for the right-arrow symbol). Rather than
revert the menu() change (where CPM-EOF mode is the default for menu
files) - change the Ctrl-AZ sequence from "premature end-of-file" to instead
send an actual Ctrl-Z character (similiar to Ctrl-AA, Ctrl-AL, etc.). This
changes the long-standing behavior of what Ctrl-AZ does, but since that was
a dubious "feature" that I'm pretty sure nobody used, I'm will to take that
chance. If you need a premature EOF now, just use a regular ole Ctrl-Z
char instead (or even the @eof@ code). Of course the msgscan.asc now has
to change accordingly.

terminal text and attributes with a linked-list. In doing so:
- the save depth is no longer fixed (at 4), but dynamic and unbounded
- the current column position is also saved/restored (bug fix)
- no more copy/pasta from sbbsdefs.h into js_console.cpp
- the JS console.saveline() and restore() methods now return Bool to indicate
  success/failure

Also, some trailing white-space was auto-removed due to local editor settings.

previous commit: don't clear the line counter or call pause() - which will
do nothing - if the console abort flag is set.