Replace #each_slice with 1.8.6 compatible iteration.
Replace #each_slice with 1.8.6 compatible iteration.

Closes gh-178

iankronquist/yard,alexdowad/yard,jreinert/yard,amclain/yard,herosky/yard,ohai/yard,ohai/yard,thomthom/yard,travis-repos/yard,amclain/yard,ohai/yard,thomthom/yard,iankronquist/yard,iankronquist/yard,amclain/yard,jreinert/yard,lsegal/yard,travis-repos/yard,alexdowad/yard,herosky/yard,jreinert/yard,thomthom/yard,alexdowad/yard,lsegal/yard,lsegal/yard,herosky/yard