previously the name converter only supported underscores.
Some gems also use dashes and the pluginator was not able
to convert these names properly. This commit fixes that
by adding the '-' to the list of allowed characters.
Coverage remained the same at 100.0% when pulling 023ccc46fec603c492a3547aab19814fd0deb07a on nwops:dash into 3382bcaebf090b4b812701aaa26f0f487c55f7e2 on rvm:master.