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
- Display post "destructiveControls" in flag instead of custom buttons
- Make flags more versatile/extensible
- Delete associated flags when a post is deleted
Uninstall the Reports extension before installing.