Simplify the appearance UI, Model & File

This changeset replaces the three color parameters "Ambient, Diffuse & Specular" with a single one called "Paint", and changes the "Shininess" parameter to one called "Shine" which runs from 0-1, is displayed as a percent, and affects both the specular color and power in the GL renderer.

**Files saved with previous versions of this branch will lose their color and shine.**