Remove API to set if a geometry requires writing to the depth buffer

Remove API to set if a geometry requires writing to the depth buffer

- Removed API to set ( and get ) if a geometry requires writing to the depth buffer when rendering
- Added a property in renderer to specify whether the renderer requires writing to the depth buffer.
- Clean-up shader hints. Removed hints which were not used (i.e never checked)

Change-Id: I4c4b4f17382cefb5b94850c4cc93e64951bf9607