Removed all calls to GrayOn/GrayOff.  That's the user's job.
Added grayscale wireframe rendering.
Changed vertex reallocation to occur whenever the number of allocated vertices for the result doesn't match the number of result vertices.
Added a basic backface culling skeleton.
Added NULL safeguard when freeing memory in X3D_Render.
Finished backface culling.
Implemented basic Painter's algorithm display.