Previously, extracted files were always overwritten (so that is the "default" for Archive.extract() and mostly what I'm specifying in the C/C++ code by default now), but this caused a problem with DIZ extraction: archives that contained multiple DIZ files (e.g in sub-directories), the last to be extracted would be used. A maximum of 3 DIZs can be extracted, so it would usually be the 3rd DIZ in the archive if there were that many.

Another solution would be to *only* extract DIZ files from the root of the archive and I should look into that as well, but the always-overwrite behavior also seemed to be wrong, so that *also* needed fixing (allow caller to control behavior).

This fixes issue #317, at least for archives where the root DIZ exists *before* any nested DIZ files. I'll have to try and create a purposeful archive to test the other conditions (where the root DIZ would appear *after* the nested DIZ(s)).

It's anticipated that this will be used for JS-populated file metadata in JSON format in the future (and not just "archive contents" in .ini format).

Also, fix the double-free issue that was occurring when moving files with extended file descriptions (sbbs_t::movefile()). This was actually the primary problem I was fixing here, but noticed the metadata issue: metadata would not have been moved along with the other file info between bases.

5 options:
- Safest Subset
- Most ASCII, Excluding Spaces (the default)
- Most ASCII, Including Spaces
- Most CP437, Excluding Spaces
- Most CP437, Including Spaces

sbbs_t::checkfname() now checks the file.can too.
new filedat.c functions:
- safest_filename() - not currently used
- illegal_filename() - returns true for a highly-suspicious (e.g. hack attempt) filename
- allowed_filename() - returns true if the filename is good for upload (assumed to be already checked to be legal as well).

Importantly, filenames beginning or ending in a '.' are now unallowed:
- 'dot files' are hidden (by default) on *nix
- files ending in a '.' are problematic on Windows

Do this in JS and use JSON for format instead of .ini.

Some archives contain exactly the same files as others, but in a different order. Believe it or not.

This will allow fast/easy display of archive contents without actually reading the archive files.

Introduces some new functions:
- list_archive_contents()
- smb_adddfile_withlist()

A new SMB convenience variable ("tail", aliased as "content" for a file).
A new file detail level ("file_detail_content", exposed in JS as FileBase.DETAIL.CONTENTS) which adds a "content" array property to file metadata objects for JS FileBase.get().

Files already added to the new filebases won't have this archive content automatically - I'm looking into that now (likely a new or updated JS script to run).

Inspired by Blocktronics (and other ANSI art group) packs' FILE_ID.DIZ/ANS files:
* Support (and prioritize) FILE_ID.ANS
* Convert ANSI color/attribute sequences in DIZ files to Ctrl-A equivalent (uses SAUCE width and ICE color, if specified)
* Don't treat DIZ as a series of lines, they're not always nowadays.
* New putmsg() mode: P_INDENT to print files indented by current column
* Display full (up to 64-char) filenames in lists when using 132+ column terminal.
* Use the Author, Group, and Title fields from the SAUCE if present/non-blank
* 2 new text.dat strings: 301 (FiAuthor) and 302 (FiGroup)
* Also fix bug with repeated Cost header field on bulk-uploaded files.

I know this'll break the *nix build (sauce.c dependency), but I'll fix that next.

Increase total extended description length from 1024 to 4000 characters. Perhaps this should be configurable?

I forget who it was that said they were still using this feature in v3.18, but here you go, it's working again (the /D and /U commands). I'm not migrating any file sender/recipient info from v3.18, so only files added after upgrading to this will be downloadable from the "user" directory (if you have one).

Something that I never implemented before but noticed is missing is the removal (or dereferencing) of user-to-user files that were sent from/to a user that is then deleted. So that's still a TODO item.

This won't impact Synchronet as it has a separate signal handling
thread, but we still need to behave properly for processes that
don't.  I'm also saying that ENOMEM does not indicate a disconnection,
though it may be better to pretend it was disconnected...

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).