Closes#4032
- Created "mobile" views: `parent-view`, `content-view` and `index-view`
- `mobile/parent-view` has three callbacks for managing layout, and a mediaQuery listener to keep in sync with the user
- content-view and index-view use their parent-views callbacks to bring themselves into and out of the viewport as appropriate
- fixed media queries for post content list from 800px to 900px
- Created `mobile-index-route` to intelligently transition to a new route on desktops (used by both PostsIndexRoute and SettingsIndexRoute)
- Extract mobile interactions from settings views to new mobile utility views
- `js-` prefixed settings view transitions
- removed unused openEditor action from PostsRoute
- removed unused mobile util "responsiveAction"
No issue
- Corrects the syntax used for the floating header gradient so it now gets prefixed correctly for Firefox
- Removes padding from `<button>` elements (fixes padding around images in buttons)
- Adds display: block; to settings images to prevent a Webkit bug which adds space under the image
- New _shame.scss to hold styles/components which need to be refactored or removed
- layout.scss and floatingheader.scss merged into global.scss/shame.scss