Groups2009 code: Code refinements
to_backend_name and to_group_name methods were removed. If a backend needs group name mapping it must handle it internally. http://hg.moinmo.in/moin/1.9-groups-dmilajevs/rev/dcbdf7e5660d
Backend's _retrieve_members and is_group methods were introduced. _load_group became method of a BaseGroup to avoid code repetition. Test for empty group was added. http://hg.moinmo.in/moin/1.9-groups-dmilajevs/rev/ca8fcf330aa8
GroupManager update/load_cache stuff was killed. http://hg.moinmo.in/moin/1.9-groups-dmilajevs/rev/c54a1ba60873