Made a bunch of massive changes to the OpenGL code

-All code now uses OpenGL 3.0, rather than 1.1
-Added resources for model data and UV maps in the AssetManager
-Completely removed RectGraphicsComponent, and drawRect(). Entities should now use the more generic base class, GraphicsComponent, which defaults to drawing textured quads.
-GraphicsComponent can now do everything that RectGraphicsComponent did, and has a scaling factor as well.
-AssetManager now loads/generates a basic default model, uv map, and shader program.
-NOTE: drawText works, but text is not very well aligned. This will be fixed soon.