#30 miscellaneous things for 0.7.12

[James Curbo]

http://www.raspberryheaven.net/~hannibal/code/combined-0.7.12.diff

This patch does three things, all optional.

1) modifies the login code to scan the user's nickname
and only allows certain characters to be used. Right
now it uses isprint() only, to allow printable
characters. The if statement could be easily changed
to disallow other characters, however.

2) Fixes a bug with MAX_HUB_NAME and memory allocation.
On my hub we use the hubname as a pseudo-IRC-topic. In
my perl script I have a bit that catches the command
"-hubname" and does two things: sends out "$HubName
<asdf>|" to everyone and updates the hub variable
"hub_name". I have changed MAX_HUB_NAME in main.h to
100 instead of the default 25, and there is a part
where this is referenced in the code that was causing
segfaults.

3) Adds a "kill_script" script message. My perl script
has an IRC gateway that needs to be shut down by a kill
signal, else it zombies when the hub is shut down and
does not die when you do !reloadscripts. We added this
signal to do just that. See my script
(http://www.raspberryheaven.net/~hannibal/code/ircbot.pl)
for details.

The only one I would really think about applying is the
second one, which is a one line change in main.c. The
others are completely optional and really only useful
to me right now. Thanks.