This is an organizational class that can update and render a bunch of FlxBasics. NOTE: Although FlxGroup extends FlxBasic, it will not automatically add itself to the global collisions quad tree, it will only add its members.
Iterator implementation for groups Support a filter method (used for iteratorAlive, iteratorDead and iteratorExists) @author Masadow
FlxSpriteGroup is a special FlxSprite that can be treated like a single sprite even if it's made up of several member sprites. It shares the FlxTypedGroup API, but it doesn't inherit from it.