synchronize GtkQTreeModel and GtkQSortFilterTreeModel APIs
Issue generated from Tuleap's migration script. Originally submitted by: Alexandre Viau (aviau)
we should bring the new GtkQTreeModel features to GtkQSortFilterTreeModel
Issue generated from Tuleap's migration script. Originally submitted by: Alexandre Viau (aviau)
we should bring the new GtkQTreeModel features to GtkQSortFilterTreeModel