Add the ability to play or shuffle a selection.
This finally allows "arbitrary" playback to be created from any
combination of songs/albums/artist/genres, rather than just from
pre-defined options.
Resolves#313.
Redocument the detail, home, image, and list modules.
Much of this project's documentation has drifted from actual
functionality, and newer code is pretty sparely documented.
This commit seeks to rectify that by redocumenting every source
file in this project.
Implement actions for selections in the home view.
Play selected and shuffle selected have been removed for now until the
queue can be properly reworked
