Factor out common code for transient objects in transient_open(). For symetry rename enc_group_close() to transcient_close().
Factor out common code for transient objects in transient_open().
For symetry rename enc_group_close() to transcient_close().

mbouyer/marine_chartplotter,mbouyer/marine_chartplotter,mbouyer/marine_chartplotter,mbouyer/marine_chartplotter