Vertrauen's FTP server gets abused by QWKnet logins sometimes and handling
the race conditions around QWK packet creation attempts is silly - there's
no legit reason why a QWKnet account needs to be logged-in multiple times
concurrently to the hub's FTP server, so reject the subsequent logins even
when they're on different hosts (as is the case with Vertrauen).

As part of this change:
- fmutex() now takes an new time_t* argument to (optionally) store the
  time of the mutex file for helping logging (locked since when?).
- time_as_hhmm() created to format a string as either HH:MM or HH:MM[a|p]
  (depending on system configuration for 12 or 24 hour time formatting).
- renamed the old hhmmtostr ()to tm_as_hhmm() (since it takes a struct tm arg)
  and have it return a non-padded string (useful in more situations without
  requiring truncation) when the sysop prefers 24-hour time.

For cases where we want to the verbal short date output, regardless of sysop
preference/configuration.

This allows us to use dstrtounix() for MM/DD/YY dates regardless of the system
configuration (sysop/locale preference).

This fixes issue with QWK route.dat file and door.sys (expiration date)
parsing where the date is/has-to-be in MM/DD/YY format, always.

Although we've added (in SBBS v3.20) configurable numeric date input/display
formats for the system, the output was still ambiguous for users (e.g.
NN/NN/NN which could be interpretted a number of ways), so I've added an option
to choose "verbal" short date formats to be displayed where possible instead.
The same value separate from the numeric format (whatever the sysop chose) is
used in the verbal date output, but since month name abbreviations are 3
characters, only one separator is used (to keep the output length fixed at 8
characters).

The new "Verbal" short date display format is choosable in the SCFG wizard and
via SCFG->System->Short Date Format.

To complete the request from: Max (WESTLINE)

  Is it possible to do a new dateformat in scfg
  In sweden we using YYYY-MM-DD format as standard.

The default will be '/'.  Technically, any separator is possible by editing
the "date_sep" value in the global section of main.ini.  SCFG allows the
most popular separators: /.- and space.

... and YYYY/MM/DD for birthdate input/display.

Now set in SCFG->System (not toggle options) and stored in the "date_fmt" key
(new) in main.ini. The old sys_misc SM_EURODATE flag is deprecated (but used
to determine the default value of date_fmt when not present).

As requested from: Max (WESTLINE)

  Is it possible to do a new dateformat in scfg
  In sweden we using YYYY-MM-DD format as standard.

Generates a "Dd Hh Mm" string from a specified number of minutes.

The goal of this commit is that: only modules that either are part-of sbbs.dll/libsbbs.so or need to link with/use that library, will #include "sbbs.h" and thus be dependent on its subsequent includes (e.g. cryptlib.h, jsapi.h). This should mean extdeps.mk can be trimmed way down.

I also removed CVS keyword/comments and trimmed up the boilerplate copyright notice in modified and added source/header files in this commit.

There is no functional change in behavior in this comment.

This means the JS global word_wrap() method has a new optional Boolean arg
as well.

Most of the copyright years in the source code were misleading (the date of
most recent publish was actually later) and all were unnecessary. I've been
removing copyright years piecemeal, for a long time, but I decided it was time
to just perform a bulk search and (mostly) replace. In some cases, I left
old copyright years on files that either are not used (and soon to be removed)
or obsolete and unlikely to ever be touched again (e.g. Win9x FOSSIL VXD). Some
of the runtime binaries still contain copyright years and those were updated to
2018.

"Change the last argument of wordwrap() to a flags argument and support
making a bare LF not be ignored."
If soft line breaks (bare LFs) are stored in the message base, they're
expected to wrapped for 80-column terminal only.

Hopefully I did this right (Deuce?).

Separated code from crc32.h into crc32.c (to allow combination of mailsrvr and sbbs into single module).