GravityControl

• Added new SonicBooster mode. (sneak by a vector sign, get a boost!)
• Added new config options
• Improved existing damage system + options.
• Did I mention the sonic freaking boosters?
• left clicking while holding a snowball reverses its polarity.

magnetic physics engine is so resource intensive it crashes servers. (disabled by default,the config option allows you to completely enable or completely disable it.)