Add no-continuation warning for Rubinius and only warn once
Add no-continuation warning for Rubinius and only warn once

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