Merge branch 'development' into loadoutScreen
Changed damage modifier to use more logical parameters.
Change the percent stuff back again. Modified javadoc to reflect changes.
Added SpecialEffect classes. Added one implementation for a special ability that deals 10 damage to all enemies on screen.
Gave player SpecialDamageAll ability. Press G to use.
Added ProjectileRain special that spawns a wall of bullets. Press G to use.
Removed ResourceIdentifier from PlayerShipImpl since its superinterface already implements it.
Extracted some methoods for clarity.
Added isDead method to Destructible.
Changed SpecialProjectileRain to be more random and look better.
Merge branch 'loadoutScreen' into development