An iterative version of quicksort, complete with visualization. It sorts 480 elements (1 pixel wide bars look nice, I think.) This has slightly worse space complexity than recursive quicksort because recursion doesn't work that well in scratch, so I had to use a stack. Also, because values can't be returned from blocks, it's somewhat hacky. However, this also will always work; the program flow is just somewhat... strange. It also features the Fisher-Yates shuffle, which is a way of generating a list of items from 1-n
