Work on various things, including a lot of work on arbitrary-size
multi-buffer vertex collections. Those are partially working now, with
two main bugs: a segfault on cleanup, and some bug probably with vertex
reuse that causes cubes to be drawn messed up.

-Peter Mawhorter
Fixed the vertex reuse issue (I had changed how the argument was
supposed to be passed without changing calls to the function).

-Peter Mawhorter