- Moves the import of plugins for both mobile and desktop from common after discourse loading, allowing plugins to overwrite
- Make desktop-option behave like the mobile-option: SCSS/CSS marked with that option will only be loaded for desktop from now on and ignored in mobile
- Add variables-keyword, allowing plugins to ship and overwrite variables before they get imported by discourse (great for theming)
- adds another :mobile-flag to register_assets
- adds test for plugin registering of assets
- load plugins when on desktop and plugins_mobile when on mobile