Added perf test for julia port of Peter Norvig's spelling corrector

This is a Julia port of Peter Norvig's spelling corrector, from http://norvig.com/spell-correct.html.

julia-users discussion is here: https://groups.google.com/forum/#!topic/julia-users/iCZe1KujkEE

Note that at the time of submission, Peter's python version is about 5-6x faster.