Raytracer supports polygons.

also moved static methods from Vector to V
Initial merge of Simple package
comapring models
Prism is added
Demo curve is added; Prism needs to be updated
Added Polygon3D back: for testing and comparing results.
Polygon Prism is fixed

CNTs constructed with Polygon3D meshes and Prisms result in identical
statistics;
Added PolygonMesh for model comparisons.
Fixes Ribbon class to behave similar to Prism/PolygonMesh
Merged Prism/Polygon3D Models

1. Ribbon model is fixed and behaves almost identically.
2. Applet has not been changed.