mrepo::repo class params to set mrepo command and possible environment to set.
trailing comma...
Enable specifying port and priority for vhost

Also clean up some double-quoted strings puppet-lint was complaining
about
No guarantee that 'mrepo::repos' will be included

Breaking dependencies on it that exist at the top-level class, and
trying to implement the anchor pattern a bit differently.

Fixes #13
Include mrepo::repos on init
Merge branch 'pr/14' into divergent
Merge branch 'pr/15' into divergent
Merge branch 'pr/16' into divergent