CCEffects - Fixes for SpriteBuilder integration

- Rework effect stack prepareForRendering so it always calls prepareForRendering
on the contained effects. Based on the return value, it then figures out if the
stitcher needs to be rerun.
- Add reader support for the new TokenArray property.
- Fix handling of empty groups in CCLightCollection.
Merge branch 'develop' into SB/lighting-integration
Merge pull request #1092 from thayerandrews/SB/lighting-integration

SpriteBuilder lighting integration