[gtk] (13 commits) ...Merge branch 'included-icons' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  ec6458d... testsuite: Consider bookmark-new as required icon (*)
  92d6f5e... Add image-missing to the internal icons (*)
  4df2a4c... icon theme: Remove fallbacks (*)
  6c4e088... resources: Include more icon directories (*)
  bcafd20... resources: Include more icons (*)
  7207c82... spin button: Use guaranteed icons (*)
  16026b6... page setup dialog: Use theme icons (*)
  ce5f198... widget-factory: Include our own icons (*)
  93514b4... sidebar demo: Use an existing icon (*)
  5f73d52... stack demo: Use the proper icon name (*)
  ffc7a81... gtk-demo: Include our own icons (*)
  4fb342f... Update check-icon-names tests (*)
  2bd9330... Merge branch 'included-icons' into 'master'

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