Change random sort to use Fisher-Yates shuffle

[d8uv]

Sorting by Math.random() doesn't give you a fast or a consistent shuffle. With that said, this shuffle is still bigger and more complicated than the naive approach, and I haven't done any formal benchmarking or testing. I leave it completely to you.

[albell]

+1. Math.random()- 0.5 doesn't give a remotely even distribution of probabilities. I've always had a superstition about this from manual testing. Digging into it a little, it's actually true! Check out:

http://phrogz.net/JS/JavaScript_Random_Array_Sort.html

Interestingly, different browsers have very different biases, but in all browsers the weightings are dramatically unequal.

A performance-optimized modified Fisher-Yates shuffle algorithm that uses a for loop instead of a while is here:

http://stackoverflow.com/a/4206715/776121

[robertocr]

+1