Grunt Clean to remove node_modules

if you run "grunt setup" it'll remove the node_modules sub-folders in addition to the usual preening and concat. Otherwise just run  `grunt clean` to remove the folders.
Useful for people who install things via bower, as it produces
an error when trying to load the Chrome extension.

EDIT: 

Looks like there were some issues running bower/grunt on Windows so some stuff switched line-endings to CRLF on Win7/with git's default core.autocrlf being set to True.

Waiting for some changes on WhisperSystems:master and then I'll re-base these changes.