3.12.0:

* Added Gtk::ActionBar.
  (Juan R. García Blanco)
* Added FlowBox example.
  (Juan R. García Blanco)
* Added HeaderBar example.
  (Juan R. García Blanco) Bug #708866
* Added ListBox example.
  (Kjell Ahlstedt)
* Added PlacesSidebar example.
  (Juan R. García Blanco)
* Added Popover example.
  (Juan R. García Blanco)
* Added Revealer example.
  (Juan R. García Blanco) Bug #705460
* Added SearchBar example.
  (Juan R. García Blanco)
* Add a multi-threaded example program.
  (Kjell Ahlstedt)
* Application example: Add a window menu.
  (Murray Cumming)
* Remove stock items and other deprecated API from the tutorial.
  (Kjell Ahlstedt)
* App_and_win_menus example: Add a menu item that sends a Gio::Notification.
  (Kjell Ahlstedt)
* ToolPalette example: Skip non-existent and large icons.
  (Kjell Ahlstedt)
* EventBox example: Make it possible to clip the label.
  (Kjell Ahlstedt)
* InfoBar example: Really show the infobar.