Mercator Rotation Fractal, R2

It's the same scale and rotation parameters as R1, but with more iterations (24 to be precise, which changed the colors a bit in a few places) and a different viewing window, namely (-1, 1) × (-1, 1).

I also made several improvements to the program. The discontinuity antialiasation is improved, and there were a few places where I optimized for speed. That, combined with the fact that this computer is a lot faster than the machine I rendered the last one on, means a lot more pixels rendered in a lot less time. I think this one took about 3 hours.