Added tweens to schema
Added TweenEngine as engine dependency
Added TweenSystem
Added actor entity tween accessor
Rotate tween with test
Move tween with test
Scale tween with test
Component field tween with test
Updated demo to use all new types of tweens
Some javadoc updated
Generalized ActorEntityAccessor into GroupAccesor
Merge pull request #348 from anserran/ec-transform

Added Tween System to allow tweens (transformations) in entities