* Add cards due view
* Add input for selecting sort (not working)
* Add methods to `Utils` to save sort to local browser storage
* CSS updates to make lists display horizontally within swimlanes
* make the page more visually pleasing
* user +viewer to display Markdown in titles
* modify `colorClass()` in Lists model to return 'list-header-{color}'
* modify `colorClass()` of Swimlanes model to return 'swimlane-{color}'