Added Utilities.LoadObjMulti

It will load an Obj file with multiple object groups, as well as their
corresponding mtl files
There seems to be an issue with normals that has existed since forever.
Fixed normal problem

Added normal visualization
woops no stop
Frustum culling!

(Works with bounding spheres at the moment until I get bounding boxes
working)
Re-did how the camera works
Fixed text being culled

oops
Fixed bounding spheres for weird bounding boxes

Also renamed Font to Text because Font was a terrible name for what it
did.