More noise

Still tinkering away at the noise library, squashing a last few bugs and cleaning stuff up. The idea to allow a fractal to have any basis function for any layer was a good one, but it did add some complexity. It makes it harder to just get a quick fractal up and going. So I added functionality to build a 'regular' simple fractal by specifying the basis function type. Lets you get a quick fractal up almost as quickly as before, when fractals were hard-set to a specific type.

The noise library is nearly complete. There are several more patterns I want to add to the 2D shapes library, that are useful for terrain generation. I've had a few requests to see the library, so I'll probably release it sometime soon.