loop over all primary classes looking for a given handle.
* src/RelLib/_Source.py (serialize, unserialize): properly save
and restore marker.
* src/RelLib/_MediaObject.py (serialize, unserialize): properly
save and restore marker.
* src/RelLib/_Place.py (serialize, unserialize): properly save and
restore marker.
* src/RelLib/_Repository.py (serialize, unserialize): properly
save and restore marker.
* src/RelLib/_Event.py (serialize, unserialize): properly save and
restore marker.
svn: r6507
python objects, so that Gramps classes are never pickled.
* Date.py, CalSdn.py: Move to RelLib.
* src/dates/Date_*.py: Use new Date.
* src/plugins/*.py: Use new Date.
* src/GrampsDb/_*.py: Use new Date, new unserialize.
* src/*.py: Use new Date.
svn: r5875