Refactoring: RegionAttachment vertices, texture->rendererObject...

- Vertices are no longer stored on RegionAttachment. The vertices are temporary state, not part of RegionAttachment's persistent state like UVs and offset.
- AtlasPage and RegionAttachment "texture" field is renamed to "rendererObject". This is a better name as it may not be a texture.
- AtlasAttachmentLoader uses the AtlasRegion as the rendererObject. This enables a renderer to use region information if needed. The page rendererObject is still available.
- Better "enum" look up for AS3.
- Unity4 example doesn't use a compressed material.
Refactoring: changed references to "bind pose" to "setup pose".

This better matches "setup mode" in the editor and we can be consistent in code and docs from now on.