3rd person, headway into playability

3rd person camera now with mouse orbit, revised gravity script to
actually drop off with the square of the distance, added a physic
material for the player, and cleaned up a lot of other things in the
scene.
Improved and refactored camera, tweaked lighting

I also re-arranged the scene to be a bit closer to perfection.  The
camera now runs on one script that I wrote all of.  Still working on
finding a good lighting solution.