Refactor of openbadges-displayer.js

Large update.

* Various dev dependency additions / removals
* **MUCH** leaner code
  * jQuery and underscore are no longer client-side dependencies
  * JS is minified with uglify and CSS is minified with clean-css through gulp-minify-css.
  * Badgelogo is now base64 included within CSS
* Now compiling coffeescript to JS and less to CSS
* Switched to gulp
  * Switched to express (from beefy) in order to use [gulp-express-service](https://www.npmjs.org/package/gulp-express-service)
* Switched from JS to CSS transitions.
* Can now install requirements and run the server with `npm start` (single line install / compile / server run)
* Fixes issue #1 #2 #4 #6