[gtk] (4 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:

  7624801... coloreditor: Set an accessible role for the swatch
  8f417f0... colorbutton: Improve accessibility
  ad68660... picture: Set alternative text as description
  17852ec... gtk-demo: Add alternative text to a GtkPicture
  a11046a... gtk-demo: Speed up image demo

Commits added to the branch:

  e2b3cba... colorbutton: Improve accessibility
  ed571ae... picture: Set alternative text as description
  ef7499a... gtk-demo: Add alternative text to a GtkPicture
  44c6619... gtk-demo: Speed up image demo