[gnome-music] (8 commits) ...artistalbumswidget: Simplify _on_model_items_changed

[Jean Felder <jfelder src gnome org>]

Summary of changes:

  69cfdff... baseview: Apply selection mode changes for the visible view (*)
  6d9ac69... coreartist: Load the model only if the artist is selected (*)
  4aaf10b... coremodel: Load the model only if the album is selected (*)
  0ecb82f... songwidget: Do not display dnd handles when show_all is cal (*)
  e3106d8... artistalbumswidget: Prevent the albums from being selectabl (*)
  53a9b0f... disclistboxwidget: Do not display disc label when setting i (*)
  ab6454d... artistalbumwidget: Correctly set discbox properties (*)
  dc7740e... artistalbumswidget: Simplify _on_model_items_changed (*)

(*) This commit already existed in another branch; no separate mail sent