use table cell background colors instead of views
switch grouping colors
allow list view controller sub-classes to add own menu items
don’t show the button menu if the button item is not enabled
also show a ‘New’ menu item besides the ‘Paste’ menu item when the add button is long-pressed in the list view controllers
rework sharing actions and add ‘Copy’, ‘carddecks:// URL’, ‘.carddeck file’ (JSON document) actions via long-press gesture