TuneIn station logos get confused when players are synchronized.

Make sure we always deal with a sync group's master object.
Merge branch 'public/7.8' into public/7.9
Bug 18109: When album view is filtered by artist role and ordered by
artist, then the pagebar gets out of sync with the content.

We need to make sure we're working on unique album.id values when
creating the index bar. Otherwise an album which has one contributor
with multiple roles would get counted twice.