Feature #407: * Chown method: destination user and group are checked, auth. manager request used. * New one.group.chown method. * New ObjectCollection class to store sets of IDs. * New RM user.addgroup user.delgroup methods, users and groups store a cross-reference ID set. * Clusters store a set of Host IDs. The RM part of the add/remove host functionality works, but should be re-done to avoid deadlocks. * Fix onedb schmea for template_pool table bug.