Jean Felder authored Feb 18, 2020 and Jean Felder committed Feb 28, 2020

This feature was lost during the core rewrite.

Everytime a change is triggered, two smart playlists might need to be
updated:
 * the PlayerPlaylist (active_playlist)
 * the currently actively viewed playlist
Besides, a smart playlist needs to be updated every time it becomes
visible.

An update method is introduced to update a smart playlist content. The
model of the SmartPlaylist is queried and compared with the previous
one to perform the correct insert and remove operations.