Add support for the IQM model format (WiP)
This is the beginning of the long journey to get animations going, which the model format used so far does not support at all. Say hello to IQM, the Inter Quake Model Format.
Before animations will work though, make sure to support rendering the models in their static/default state, which is exactly what this commit does.
Check out what it looked like right before, when it was almost working: