xml_func.py: _map: Instead of _closed special entry, make all maps closed by default and open them if special entry "*=*" is present. Support using a _map to filter values by interpreting special entry "*=" as removing all values not explicitly specified, and by interpreting special value "*" as keeping input value the same.
xml_func.py: _map: Instead of _closed special entry, make all maps closed by default and open them if special entry "*=*" is present. Support using a _map to filter values by interpreting special entry "*=" as removing all values not explicitly specified, and by interpreting special value "*" as keeping input value the same.