Make cube rendering use a similar codepath to md3

- Still trying to isolate error(s) with md3 model loading
- Going to continune to collapse the code path between the two to try to
isolate the error
- Added some documentation on Mesh methods
Shuffle around the assets
Refactor enums in Rendering.h into namespaces
Completely refactor MD3Model

- Doesn't fix the issue I'm having, but makes me feel better about the
code since it feels a bit more inline with other binary file loaders
I've seen out there
- Load the whole file into a memory buffer and work on this instead of
seeking around the file
Fix trackball error w/ imaginary numbers

- The ScreenToTrackballCoordinates function does not return normalized
vectors
- So when I went to determine the angle between two un-normalized
vectors, it was possible that I would try to take acos(beta) where beta
> 1, which would give imaginary results and absolutely destroy the
camera matrix
- Fixed this by normalizing the dot product before taking acos
Remove debug statement from trackball