Add FlxTypedSpriteGroup
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into FlxTypedSpriteGroup

Conflicts:
	flixel/group/FlxSpriteGroup.hx
FlxTypedSpriteGroup: opimization via statically typed _sprites array
FlxTypedSpriteGroup: also use _sprites for reset()
Correction for the description of FlxSprite.setColorTransform()
Make FlxSprite.colorTransform (default, null) and remove _colorTransform
Use FlxPoint.get() and FlxRect.get() everywhere

- removed FlxObject._pZero (not used anywhere + doesn't seem necessary anymore with pooling)
- small style cleanup
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into FlxTypedSpriteGroup

Conflicts:
	flixel/group/FlxSpriteGroup.hx
Some improvements for FlxObject

- removed cachedGraphics, region and framesData and pixelPerfectRender - FlxObject should not have graphical data. They are now introduced in FlxSprite and FlxTilemap.
- moved static functions and variables to the top
- made debugBoundingBoxColor a Null<Int>, making _boundingBoxColorOverritten obsolete (null means: use the default colors)
Cleanup for the overllaCleanup for the overlapping functions in FlxTilemap and FlxObject
Add FlxSpriteUtil.bound()
Make FlxGroup.overlaps() private
FlxTypedSpriteGroup: optimize transformChildren() and multiTransformChildren()
FlxText.setFormat(): add missing docs for EmbeddedFont
FlxTypedGroup.replace(): better docs
Better docs for FlxText.systemFont
FlxText.embedded: better docs + change to (get, never)
FlxTypedSpriteGroup: optimization for add()
FlxText.addFilter(): fix widthInc and heightInc (thanks @l0rb) + inline
FlxTypedGroup: slightly nicer syntax for multiTransformChildren()