Add play and shuffle options for all song menus.
These will override the shuffle state, unlike other song play
interactions.
This required a good bit of refactoring to menu, some of which
might be ported to other commands in future changes.
Bit of a megapatch that:
- Adds dedicated play, shuffle, and view items to all item menus
(songs haven't been fully implemented yet)
- Adds icons to all item menus
- Re-adds enabled/disabled items to menus
- Makes menu action naming conventions more consistent with the rest
of the app
