Now only the subscriptions from the selected group by the user will be
loaded.
Also add an option to decide how much time have to pass since the last
refresh before the subscription is deemed as not up to date. This helps
when a subscription appear in multiple groups, since updating in one
will not require to be fetched again in the others.
-Added play queue dropdown to playlist info items.
-Added Channel Play Queue.
-Renamed External Play Queue to Playlist Play Queue.
-Modified Playlist Play Queue to allow loading from initial state.
