gtk+-2.0, gtk+-3.0: Further syncing with introspection annotations

(cherry picked from commit 370cd5b6eccbe884457b42557b9b647c914f7c2f)
gtk+-3.0: Update to 3.14.1

(cherry picked from commit 08254c8d82b0c9bc58716ccb5440461e4d806100)
gtk+-3.0: Fix lost special includes for GtkIMContext/GtkPlug/GtkSocket

(cherry picked from commit 68f670a6cef5355227854b6dfdfd52a87d5c58dc)