#1 Improve Poly UV Coords

[Jess Wright]

Improve the algorithm that assigns UV coordinates.

I think there is a bug that causes the UV scaling algorithm to do the opposite of what was intended. Currently the texture gets smaller as the faces get larger, I think the opposite was intended. Also, it fails on small faces (show a solid colour).

The reason I write improve rather than just fix that bug, is that I don't like how the texture scale change looks as I change the size of a polyhedron. It distracts from what is happening. The apparent texture scale needs to either stay the same, or perhaps there is a way to have variable scale that will look less distracting.