Polygon drawing segfaults.

[Seth Hetu]

The drawing code is sometimes given null vertices. (It is possible that their weights are zero, and this may actually be part of GLU.)

For now, I've disabled them; a proper fix should be implemented though.

This is easiest to see by starting a fight with Tor; his opening animation or his "sweep" background attack will likely cause this.

[Seth Hetu]

Fixed.