#350 create a visual editor for properties

[Hamlet D'Arcy]

I'd really like a CodeNarc properties visual editor. You could run it from the command line or through the Grails plugin. It could pop open a Swing UI that looks like the IDEA inspections UI. That would be a nice way to edit rule. But I'd want the feature to use only core JDK/Groovy classes so we don't introduce extra dependencies.