CCBReader + CCLightNode - Support for light property animations

- Add CCBActionTweenColor, an internal action for tweening color properties.
- Handle CCLightNode's properties in CCActionManager's actionFromKeyframe0: andKeyframe1: ... method
- Implement copyWithZone: on CCActionTween to fix an exception when chaining tween sequences together. Without this we end up with an uninitialized tween object with a nil property key.
CCAnimationManager used to contain its own CCB Action methods however they were refactored into the CCAction family. `CCBActionTweenColor` would be more consistent as `CCActionTweenColor` and reside within `CCActionInterval`