Support more of FlxSprite's properties in FlxSpriteGroup
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev_FlxSpriteGroup

Conflicts:
	flixel/group/FlxSpriteGroup.hx
Update FlxSpriteGroup to include both the changes to add() and the new properties
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev_FlxSpriteGroup

Conflicts:
	flixel/group/FlxSpriteGroup.hx
Merge pull request #590 from Gama11/dev_FlxSpriteGroup

Support more of FlxSprite's properties in FlxSpriteGroup, closes #560