Radix Sort implemented in java and C++ and benchmark code for [0].

The current version lacks a few small optimizations described in [1], which
could be relevant for sorting arrays with non random values.

Only positive integers are supported, but to make it work with signed
integers should be a trivial exercise.

 - Erik Gorset

[0] http://erik.gorset.no/2011/04/radix-sort-is-faster-than-quicksort.html
[1] http://ntnu.diva-portal.org/smash/record.jsf?parentRecord=diva2:124514&pid=diva2:124519