Add sample project and basic debugging instructions

@ivmarkov -> I've added some basic instructions to the plugin so we can share the repo as-is.  I joined the gwt contributor hangout, and it seems there's plenty of interest in using the plugin.

So, if you're around, I would like to get this pull request reviewed and merged so I can post on G+ soon.  If not, I may just merge it myself, since it's just instructions and the gwtproject.zip file.