Effect stacking rewrite 

Refactored CCEffectNode to support stacking of CCEffects which contain multiple render passes.

TODO:
Add CCEffects to sprites
Improve CCEffectNodes initWithSize logic, CCEffectNode should have an option to calcualte it's size based on children whenever possible. 
Make CCEffectNode SpriteBuilder friendly by ensuring that everything can be set through properties. 

Sample project:
https://github.com/osinoleg/effectsDemo