Add a control for the size of mutations.
The mutation size control doesn't apply to the wheel positions.
Instead, when the mutation rate is high and the mutation size is low,
use the mutation size to limit the rate of wheel position mutations.
We generate a skewed distribution.  Use it to prefer the best performers.
Use a simpler calculation of the exponentially decaying distribution.
I've made it slightly flatter too.
Merge pull request #1 from rcls/push

Push