update grunt file to put everything in dist/dev and dist/prod. 

This pull gives us a dist folder similar to what was detailed in issue #21. The only difference is that I created a dev folder where css and js was not minified/compressed and a prod folder where they are. If everyone's OK with the changes I'll merge them.

Thanks,
Jon
will have to verify that this doesn't break sandbox upon deployment, but otherwise LGTM.