CCEffects - Stack constructors, bloom fixes, and stacking fixes

- Add constructors to CCEffectStack that match those of CCActionSequence
- Fix intensity and threshold math in CCEffectBloom
- Fix texture coordinate math in reflection, refraction, and glass so they render correctly into intermediate render targets.
- Fix a bug in CCSprite with texture coordinate setup when there is a normal map but no main texture.
- Add tests of the luminance threshold to the bloom effect test.