Merged Robert's pull request for Graphics Optimization/Audio Patch.

From pull request:

"Refactored walls/floors/cubes in the graphics system and doubled
the speed of games by using the currently bound texture
memorization macro. Also applied a patch to audio as I wasnt
originally using a pointer array, all tested and good. Pull when
ready."

Minor merge conflicts were handled.
The changes have been tested and confirmed to work.