Finish Polygon and Polyhedron classes.

[juj]

Both classes Polygon and Polyhedron are implemented somewhat naively, and several collision tests are written in a very slow manner, and the functionality not completely tested.

Finalize these class structures.

[juj]

It was reported that the Polygon::Triangulate crashes on some inputs:

19:03 < UltraLazer> clb_, it does the return t when its not CCW or whatever 19:03 < UltraLazer> and the reversal just makes it endlessly recurse

The function needs to be examined in closer detail with a few test cases.