[gtk] (15 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:

  70636ca... widget-factory: Improve the error states example

Commits added to the branch:

  cb7c903... gtkassistant: Minor docstring wording changes (*)
  667b3b1... pathbar: Set .slider-button style class to slider buttons a (*)
  5e35ca5... Merge branch 'slider-button-style-class-again' into 'master (*)
  303e023... Merge branch 'gtkassistant_docstring' into 'master' (*)
  a0af12e... Update Polish translation (*)
  aabb713... Adwaita: error labels insensitive & backdrop states (*)
  581f224... Merge branch 'wip/jimmac/error-labels-insensitive' into 'ma (*)
  29d7d65... Update Kazakh translation (*)
  e35c000... Update Galician translation (*)
  bca6113... Update Indonesian translation (*)
  1dcb68c... Update Kazakh translation (*)
  5b35c5f... Update Japanese translation (*)
  bcd0a9e... Update Japanese translation (*)
  8acd60f... widget-factory: Improve the error states example (*)
  ec81ccd... label: Try to avoid a pango_layout_get_extents call

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