Support Term::ReadLine::Perl5

Enable autocomplete in Term::ReadLine::Perl5, and make output of Term::ReadLine::Perl5 compatible with Term::ReadLine::Gnu.

It is a little hard to install Term::ReadLine::Gnu in OS X because of license problem.
So, if autocomplete can be used with Term::ReadLine::Perl5 (this doesn't cause license problem), it become more useful.