Removed all references to 'run'.
Converted the map_space() base class method into the __init__() method.
Fixed a function vs. arg name clash.
Improvements to the dx.execute() user function.
Completed the run() function docstring.
Changed how the OpenDX map type string is matched.
Added a missing import.
Fixes for the interface of the map() user function.
More fixes for the system tests of the OpenDX mapping of model-free spaces.
Fixes for the system tests of the OpenDX mapping of model-free spaces.