the 'keys' argument is optional. If no keys are specified (or NULL), then any/
all non-numeric keys are considered valid input and may be returned by this
function/method.

as well as the auxattr "Attach" when either FILEATTACH or MIMEATTACH is set
(requires an updated MsgAttr line in text.dat).

I know... this list of %s's was a bad idea to begin with, but oh well.

after sending via POP3 (the MSG_READ attribute flag is already indicating that).

purpose

- votes
- priority
- delivery_attempts

headers).
Don't reference the (currently unused) times_downloaded and last_downloaded
msghdr_t elements/properties.
Set the current node action value *before* calling the scanposts_mod
("Scan Msgs module") in sbbs_t::scanposts().

the (never used) SMB_PRIORITY 32-bit hfield (0 = default/highest priority), to
a new fixed message header field (8-bit) following the X-Priority header field
numbering scheme: 1 = highest, 3 = normal, 5 = lowest and 0 = unspecified.

Expanded codes will not *not* go beyond the terminal column width (minus 1).
If you need the old/wrap behavior, add a "-W" modifier to your @-code.
If a length value is specified with -W, it is ignored.

- MSG_TO, MSG_FROM, MSG_SUBJECT now reflect the header values passed
  to sbbs_t::show_msghdr(), JS bbs.show_msg_header() and not necessarily the
  actual stored (e.g. MIME-encoded) header values.

New codes:
- MSG_CC - reflect a message's CC list, if it has one
- DATETIMEZONE - combines DATETIME and TIMEZONE in one string

used to display a CC list, when applicable.

"read mail" module is executed, so that the node action is correct more often.

show_msghdr(), over-riding the values from the passed smbmsg_t. This is useful
for, say, displaying MIME-decoded values rather than the MIME-encoded versions
of the header fields that you often find in email today.

Copy the upvotes, downvotes, and total_votes to the smbmsg_t, replicating
what is done in sbbs_t::scanposts() - these are used by sbbs_t::show_msghdr()
so we need to copy them if we're going to be replicating that functionality
(showing up/down votes and score) in message headers shown with bbs.show_msg()
and bbs.show_msg_header().

angle brackets in the "RCPT TO" command sent to the SMTP server. This is an old
bug but now appears because we are now (recently) actually storing the SMTP
forward-path in the message header.

settings affect both NetMail and EchoMail import/export.

Renamed MIMEDecodedPlainText to MIMEDecodedPlainTextFmt
(since it is now a printf-style format string).
No special handling of non US-ASCII (e.g. UTF-8) characters... yet.

- mime_version (from the message header, if MIME)
- content_type (from the messgae header, if MIME)
- charset (from the plain-text MIME portion content-type header field)

content-type "charset" parameter value and store in the (new) smbmsg_t.charset.
This is a heap-allocated copy of the text from the message body, so it must be
freed in smb_freemsgmem(). When NULL, the charset can be assumed to be
US-ASCII.

(when set to Yes).

The default is off (no stripping). Previously, Soft-CRs were always stripped,
but this behavior is now seen as an anachronism as CP437 char 141 is an
important non-English laguage character and used as such in FidoNet msgs.

in switch

nicely when displaying at various terminal widths.

For QuickBBS editors, the default will be the same as previous behavior: to
convert Soft-CRs to Hard-CRs (CRLFs).
For non-QuickBBS editors, the default will be to treat Soft-CRs as any other
valid printable character in the text ("Retain").
A 3rd option is available to strip Soft-CRs completely from the generated
message text.

For QuickBBS editors, the default will be the same as previous behavior: to
convert Soft-CRs to Hard-CRs (CRLFs).
For non-QuickBBS editors, the default will be to treat Soft-CRs as any other
valid printable character in the text ("Retain").
A 3rd option is available to strip Soft-CRs completely from the generated
message text.

when the user is using the internal msg editor (useron_xedit == 0) and
replying to a message.

Refer to the dubious get_msg_body() feature of dot-stuffing as that
("dot-stuffing") and not "rfc822-encoding" - because it isn't.
dot-stuffing is a requirment of SMTP (RFC*821) and NNTP, not RFC822 (oops).

- to_list (RFC822TO, previosuly unavailable via JS)
- cc_list
- replyto_list (RFC822REPLYTO, previously unavailable via JS)

Added RFC822FROM to the "field_list" array (previously unavailable via JS).
Removed SMB_CARBONCOPY from the "field_list" (now duplicated in cc_list).

headers

pointer - apparently this has never actually been used before.

- to_list
- cc_list
- replyto_list

These are all comma-separated lists of names/addresses, RFC-822 style
(so quotes and angle-brackets and all that jazz preserved/included)

New text.dat strings:
 - HitYourBackspaceKey
 - CharacterReceivedFmt
 - InvalidBackspaceKeyFmt
 - SwapDeleteKeyQ
 - PetTermDetected

Fix up some message header field lengths.