Renamed Mask Trader to EntityNPCMaskTrader
Moved IVillageDefender to AI package
Renamed Mask Trader to EntityNPCMaskTrader
Added IEntityEvil

- Interface for entities affected by Light Arrows
- Changed EntityCustomArrow calculateDamage method to return a float
instead of an int
Added IMeleeAttacker and EntityMeleeTracker

Used in combination, allows melee mobs to more accurately determine
whether an attack should 'hit'
Added IModelBiped

Allows biped-like models using the GenericRenderLiving to easily render
held items and helmets