This adds a WIP ContentView for displaying a cover art
oriented browser. The Show class was updated to expose
the needed properties to QML correctly.
This introducted the use of @pyqtSlot to expose functions
to QML (as opposed to properties).
Basic UI outline with keyboard control. Python database
object is exposed to QML and data can be queried from its methods.
This should provide a generic structure that different UI themes
can be built around.
restitux