Tube bump

Since the last pull request hadn't been finished yet, and since Amy wanted some depth specific functions, I decided to add them in real quick before resubmitting the pull request.

Basically added files for the bump mapping of the track. The track is now a .trk file and the file loading has been altered to support loading in the trk file. You can now also load in a bump map for an object by passing it in as a second texture after the first (in all of the loadModelFromFile functions).

Some alpha transparency code is in there as well. It's not being used, but is there in case we want to use it.