Add a RenderState member for cull face side.

Add a new RenderState variable named 'cullFaceSide' for changing between
FRONT, BACK and FRONT_AND_BACK values.

This is useful in same materials, such as when implementing cel shading.
Fixed the character sample for Android
Fixed bug in fileExists() for Android when loading textures that use an alias.
Merge pull request #1004 from dgough/next

Fixed the character sample for Android
Added some missing stuff for the lua bindings.
Added missing include for lua bindings.
Merge pull request #1003 from rgngl/next

Add a RenderState member for cull face side.