Fix Vector2d.distance method.
Temp workaround on RectCollider/DisplayObject collidePosition.
Add DARKER to CompositeOperation constants.
Remove DARKER (not supported anymore)
Add SoundManager2 as submodule.
Add fadeIn / fadeOut support to Scenes.
Don't use the last added scene as the current one.
Fix enter/leave collision with multiple objects.
Add Events.SCENE_ACTIVE broadcast event.
Trigger events when fadeIn / fadeOut starts.
Second parameter on Vector2d#scale is optional.
Only render visible Scenes.
Add DisplayObjectContainer#broadcast method, which broadcast triggers on children.
Add Triggerable#hasBehaviour method.
Restore viewport translation when switching scenes.
Add loaded state on Sprite.
Add SpriteSheet#stop method, to stop current animation.

Also fix rendering collider stroke on debug mode.
Add important TODO on README.