3.3.1

gcr 3.3.1
 - Add function to get elements of union collection
 - Add gck_slot_enumerate_objects() function
 - Enumerator can now retrieve object attributes
 - Add gck_session_find_handles() and friends
 - Add gnupg and password icons
 - Function to notify that certificate changed
 - Update glib dependency for 2.30.0
 - Build, translation and documentation fixes