Switch font to Roboto

Switch font to Roboto: https://github.com/uProxy/uproxy/issues/577
* Created src/fonts directory
 * Added Roboto.css (copied from http://fonts.googleapis.com/css?family=Roboto:300,400)
 * Added all the .woff2 files depended on by Roboto.css to src/fonts
* Updated Gruntfile.coffee to copy fonts to Chrome/FF directories
* Updated css throughout uProxy to use Roboto font (currently all font-weight 400, will go over with Izzie later to determine the best font-weights for various elements)
* Also updated css to prevent word-wrap that results in Roboto being slightly bigger than our previous eurostyle font.

Tested in Chrome, Firefox (up to login screen, verified Roboto works there too), re-ran grunt test