This includes an API endpoint for fetching the list of possible
drivers and their configuration fields. In the future, this can
be extended to include more meta information about each field.
* Allow admins to see last online text
* Use viewLastSeenAt permission
* Move permission to UserSerializer, removed from ForumSerializer
* Remove extra comma from ForumSerializer to keep diff clean
* Add permission to new seed migration
* Run extenders exported by extensions
* Add some basic extenders
* Patch Mithril as the very first thing so extension code can run safely
* Load the payload into the app before booting extensions
* Setup default routes before booting extensions
* 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"
* Refactor JS initializers into Application subclasses
* Maintain partial compatibility API (importing from absolute paths) for extensions
* Remove minification responsibility from PHP asset compiler
* Restructure `less` directory
