reverse and per-ring draw mode

In reverse, innermost ring fill test must be steps < minimum size AND steps < previous radius. This prevents possible holes when switching from forward to reverse, e.g. in lotus light.

The new freedoms must have a price, let's see:

250 iters of default patch, total time spent in Draw:

1.0.64:
.2269
.2237
.2263
.2251
AVG=.2255

1.0.63:
.2256
.2255
.2271
.2273
AVG=.2263

It got faster? Not likely. Try again using 250 iters of Pinwheel No Rand:

1.0.64
.5856
.5863
.5852
.5857
AVG=.5857

1.0.63
.5876
.5854
.5850
.5874
AVG=.5863

Very strange. Try a longer test? 1000 iters, window maximized, Pinwheel no rand with Ring Growth = 3 and Canvas Size = 300:

1.0.64
17.779
17.784
17.770
17.762

1.0.63
17.780
17.780
17.797

1.0.61 (no reverse or per-ring draw at all)
17.789
17.776
17.793

Well, somehow it got faster...