This ocmmit adds a LiveTvChannels page for displaying the programs that
are now playing.
The section Live TV Channels on the main page now shows the TV channel
list in order of the channel number.
Additionally, it fixes an issue in ApiModel, where it would not reload
when a new loader was assigned. This is now fixed and some code on pages
that worked around this fix has been removed.
* Show the now playing cover when playing an item, otherwise show the
collection cover.
* ItemModelLoaders now correctly expose list properties of non-built-in
Qt objects
* toString is now implemented for lists, fixing some query
construction code.
* PlaybackManager now clears the playlist when playing a single item to
prevent weird behaviour.
* The covers are slightly updated.