Implement radixSort

radixSort is a sort routine that runs in exactly O(k*n) time; here,
k is 8.  It should be much faster than quicksort for large values
of n.
Add documentation for radixSort
Remove requirement to pass B=128 to radixSort
Fix style issues in radixSort
Merge pull request #42 from thirtythreeforty/radixsort

Radixsort