atkobject: add atk_object_peek_parent

https://bugzilla.gnome.org/show_bug.cgi?id=720095
roles: add roles for description lists

https://bugzilla.gnome.org/show_bug.cgi?id=720065
Deprecate connect/remove_property_change_handler

Another utility method that ATK should not provide. And not used
at all in any case.