Texture Mapping

I've actually had texture mapping working for a while now, but a few weeks ago I decided to go back and re-work all of my base rendering code before working on any more advanced functionality.

This is the current state of the renderer. I was able to add another 1-2 FPS by streamlining my drawing loop counters.

And now the reason for this post: texture mapping. I think it's looking pretty good so far, but there's still some features I'd like to add. Performance doesn't seem to be doing too badly, but I'd like to tweak it to get an extra few FPS if at all possible.