[gtk] (6 commits) Non-fast-forward update to branch matthiasc/for-master

[Matthias Clasen <matthiasc src gnome org>]

The branch 'matthiasc/for-master' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  87d5e53... gtk-demo: Bring back the applauncher demo
  fe60972... listview: Add an example to the docs

Commits added to the branch:

  5059854... reftest: Clean up reftest_inhibit_snapshot() (*)
  d3e0a1f... Avoid quadratic slowdown in gtk_widget_add() (*)
  5535b26... Merge branch 'fix-quadratic-add' into 'master' (*)
  672413f... Merge branch 'cleanup-snapshot-inhibit' into 'master' (*)
  669a6dd... gtk-demo: Bring back the applauncher demo
  2437c5a... listview: Add an example to the docs

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