2.15.5 (unstable):
(2.15.4 was skipped)

* Activatable: reset_vfunc() renamed to sync_action_properties_vfunc().
  (Murray Cumming)
* Builder:
  - create_from_file(), add_from_file(), create_from_string(): Add method 
  overloads that take char* to avoid ambiguity.
  - get_widget_derived(): Correct reference-counting.
  (Murray Cumming)
* FileChooserButton: Add file_set signal.
  (Murray Cumming)
* Stock: Added CAPS_LOCK_WARNING.
* Added interfaces, but we can't use them yet without breaking ABI:
  Activatable, Orientation.