Bezier curve rasterizer.

De Casteljau Bezier rasterizer is faster, but currently rasterizing curves with cusps sligtly wrong. It doesn't really matter in practice.

AFD tesselator is somewhat slower, but does cusps better.

McSeem rasterizer should have the best quality, bit it is the slowest method. Basically, you will never notice any visial difference (and this code is not really debugged), so you probably should not use it. It is there for further experiments.