CCEffectNode - Fix a bunch of sizing issues and add tests for them

- Refactor CCRenderTexture's create method into create and createTextureAndFboWithPixelSize. In CCEffectNode, override the create method so pixel size is computed correctly. This fixes effect node's parent relative sizing while leaving render texture the same (because render texture needs even more changes that I don't want to tackle right now).
- Override setContentSizeType on effect node so it also marks the content size as dirty when it changes.
- If content size has changed since the last visit, destroy any allocated resources and recreate them (as CCRenderTexture already does).
- Pass the content size in points to CCEffectRenderer from sprite and effect node.
- Add a bunch of effect node sizing tests.
Okay. That makes sense for CCRenderTexture. CCEffectNode actually only has auto-draw so I think the "check the current dimensions against the texture dimensions" fix would work there no?

For CCRenderTexture, could we add another mode so the options are:

- Manual draw
- Auto draw
- Manual draw but auto-draw if it is determined that the dimensions are invalid.

Or is it better to just leave CCRenderTexture along until version 4 when we have more leeway to change its behavior?