#11 Use space filling curve to paint the fractal.

[Jason McGuiness]

'Coz it would look way cool to generate the fractal by using a space-filling, "Peano" curve (a fractal itself) rather than a boring raster scan (which it currently uses). Use a map of length along curve to pixel coords. Divide up length into a number of sections. Fine for powers of 4. What about other numbers? Use different space filling curves according to number of threads?