Small improvements in integrating with mac osx
Abstract out entity drawing
Adjustments for building on MACOS
Add num_triangles to buffer class
Append model header to camera header
Expose buffer to public space in class
Change to font to sans
Fix some compiler errors on mac
Update documentation
Add support for windows

- Revert some c99 features to c89
- Temporarily disabled skybox loading/rendering
- Add os_properties.h for os specific behavior
Change some shader error logging
Merge windows changes