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.
Update ATK authors and doap file based on last two years activity
role: add some checks on atk_role_register for wrong role names

Related with downstream bug:
https://bugzilla.redhat.com/show_bug.cgi?id=983891
role: deprecate atk_role_register

https://bugzilla.gnome.org/show_bug.cgi?id=720117