OPENGL: Release old texture name before creating a new one.

This prevents any texture name leaks (and thus memory leaks) on
recreateInternalTexture calls.
OPENGL: Add notification function about context destruction.
OPENGLSDL: Notify OpenGL manager about context destruction.
TIZEN: Notify OpenGL manager about context destruction.
OPENGL: Rename notifyContextChange to notifyContextCreate.
OPENGL: Refactor texture instantiation.
OPENGL: Properly setup full game palette on video mode change if required.