Comment 1 for bug 1568046

I'd call this one a bitesize bug, and suggest taking all the similar ancestor and descendant functions for org units from Open-ILS/src/sql/Pg/020.schema.functions.sql and simply translating them for use with the group tree. Whoever does this can just ignore any functions that have "_at_depth" in their name, as that uses org unit type information which doesn't have an analog in groups.