add support for no families or parents
* src/GrampsDb/_GrampsBSDDB.py: txn handling for get_handles
* src/GrampsDb/_GrampsDbBase.py: txn handling for get_handles
* src/GrampsDb/_GrampsGEDDB.py: txn handling for get_handles
* src/GrampsDb/_GrampsXMLDb.py: txn handling for get_handles
svn: r5707
* src/PeopleModel.py: don't access db maps directly
* src/FamilyView.py: add gender symbol to primary person
* src/GrampsDb/_GrampsBSDDB.py: provide access functions to avoid
redirect map access
* src/GrampsDb/_GrampsDbBase.py: provide access functions to avoid
redirect map access
* src/GrampsDb/_ReadGedcom.py: don't access db maps directly
svn: r5689
* src/const.py.in: Add directory for the db environment.
* src/GrampsDb/_GrampsDbBase.py: Use new logging;
(get_number_of_repositories): add method; (_del_*): add
placeholder methods -- must be overriden in derived classes.
* src/GrampsDb/_GrampsBSDDB.py: Use new logging; Add txn attribute
to the database; (open_table): rename dbopen; (get_*_cursor): Pass
txn to cursor constructors; (load): Open environment with
transaction-capable flags, open tables with AUTO_COMMIT flag;
(rebuild): use txn; (_delete_primary_from_reference_map): Use txn;
(_update_reference_map): Use txn; (_del_*)L Use txn; (remove_*):
remove unneeded functions (already in DbBase);
(_get_obj_from_gramps_id): Use txn;
(_commit_base,_do_commit,_find_from_handle): Add and use txn;
(transaction_commit): create and commit txn; do not sync().
svn: r5682
