* Remove inbox-specific class, widen single column.
* Create user preference for homescreen column layout.
* Add display options "tab" to homescreen.
* Style display options.
* Tweak homepage layout option values.
* Add tracks events for homepage layout.
* Add test coverage for homescreen display options.
* No need to use Fragment component.
* Use named exports.
* Fix display options styling on mobile/narrow viewports.
Don't show the options at all if we're forcing single column.
* Fix linting error.
Jeff Stieler