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...

This reverts commit 6a4fbf28.

Addresses issue #239

Renamed from *.asc to *.msg
Replaced mouse hot-spot @-codes with the color-coded hotspots
Removed trailling newline in head.* to avoid line-wrap in PabloDraw
on @ include line
The Sysop Menu line still wraps (in PD) - no easy solution for that
just yet.

For nickshanks1 in IRC.

As reported by Gamgee (PALANT), the MAILW:0 and MAIL:1 lines didn't display
correctly (weren't justified) because of the combination of colons and dash.
Using MAILW#0-L and MAILW#1-L (replacing colons with hash, ugh) would have
also fixed the issue, but the pipe is the newly preferred method of @-code
format arguments, so just do that through-out the file, leaving the colons.
Help save the colons!

As was observed by David Westphalen on Facebook:

The call numbers are messed up on the main menu. Says "Calls 8702 of 1615".
Is there a way to fix this? Shouldn't it say "Calls 1615 of 8702"?

The numbers were just from different statistics. They should have more
correlation to each other now.

- JS system.operator_available property (read/writeable)
- SYSAVAIL @-code which expands to LiSysopAvailable or LiSysopNotAvailable
  (use the new SYSAVAIL @-code in the chat menu to show availabilty to chat)
- ;avail sysop command (in str_cmds.js) to toggle sysop availability
- Changed LiSysopIs text.dat string to be a format string (include %s) and
  the trailing \r\n, so that it can be used in str_cmds.js or anywhere else
  to report sysop availability to chat, or can be set to blank string to
  display nothing (this would not work previously).

regular users (non-sysops), as reported by WitNik (thanks!

Rename from .asc to .msg.
Remove the bi-directional xfer command (no one has/uses these any more).

Also make e-mail menu 40-column happy.
Rename to .msg to make PabloDraw play nice.

Added EVAL and ECHO commands (very useful for testing/debugging).

I put these in the "Viewing" group rather than reformat the entire menu.
Probably more are missing, but running out of room to fit on an 80x24 screen
anyway.
Edited with PabloDraw, so using the new CLEAR @-code and includes a ^AZ
terminator.

and the forced-password-change interval.