Add option to determine number of iterations based on statistical significance

[nolanlawson]

One nice feature of Benchmark.js is that it chooses the number of iterations to run based on statistical significance. (It seems based on Mann-Whitney 95% confidence, see source here.)

This would be a nice feature to have in Best, rather than having to choose the number of iterations manually.

[jasonsilberman]

I agree this would be great. I don’t think this will make 4.0, but hopefully in a later version this can be added!