Zombie Fortress 0.5.4 Released

The biggest change this version is the implementation of the new round timer that is now run by the plugin instead by TF2. This basically removes the power from map makers to affect the round timer.

Changes from 0.5.3 to 0.5.4:
- Rounds will now always last 5 minutes. This is no longer a variable that mappers can affect.
- When a zombie is killed 3 seconds is subtracted from the clock.
- Snipers when killing a zombie, now recover 50 health instead of 25.
- Auto-balance has been made further reliable.
- Spy cloak now lasts 33 seconds before the spy has to uncloak and recharge his cloak meter.
- Minor fixes all around.