Gang Mode r2

First big iteration on Gang Mode. 

### Changes ###
- There will only be one boss per gang.
- Config option continuous_round_gang added, defaulting to off. Mostly for debugging purposes.

**Conversion**
- Flash conversion replaced with new special pens gang bosses spawn with. tiny prick
- The pens are silent and never burn out, but they have a cooldown between conversions that get longer the larger your gang is
- The pens will blink while in cooldown and will vibrate to notify the user when it's ready for use :)
- The pen otherwise looks and behaves exactly like a regular pen. Only gang bosses can use their special function.

**Weapons**
- Recallers can now be used to purchase Pistols, Ammo, and extra Recruitment Pens using points.
- Recallers get points over time. The point rate is slower the larger the gang is.

### Bug Fixes ###
- Gang bosses will no longer count as dead if their player disconnects from the server
- Gang bosses can no longer be deconverted
- Team Antag icons will now update properly when they are used outside of their game modes