Fixed some bugs and added target negation

- You can now negate a targeting directive using '!'. For example,
typing 'sh_rr !^' will force everyone except yourself into the ready
room.
- Fixed the pregame 5 second countdown from being sent many times and
thus throwing the timing off.
- Fixed console command errors from causing a script error when ran from
the server console.
- Fixed targetting guests with %guest causing a script error.