* Migrate homescreen specific backend code to its own class.
* Default to single column homescreen.
Create an option to handle the default homescreen layout value.
* Potentially reset sticky column when layout is changed.
* Move homescreen components to their new locations.
* Clean up defunct CSS.
* Default to the two-column layout on existing stores.
* Remove header from inbox notes.
* Add "your store today" header on two column homescreens.
* Set default homescreen layout to two columns when task list is complete or hidden.
* Remove unused variables.
* Add sticky scrolling behavior to both homepage columns.