Webpack (#18)

See https://github.com/flarum/core/pull/1367

* Replace gulp with webpack and npm scripts for JS compilation
* Set up Travis CI to commit compiled JS
* Restructure `js` directory; only one instance of npm, forum/admin are "submodules"
* Restructure `less` directory

extensions/suspend/.gitignore

@@ -2,5 +2,5 @@
 composer.phar
 .DS_Store
 Thumbs.db
-bower_components
 node_modules
+js/dist/*