Add detmap

>> dso = add_detmap(dso,detector_map_file)

• IXTdata_source operation
• dso is an IXTdata_source
• detector_map_file is a string defining the location of the detector map file to be loaded, eg. 'X:\mapfiles\inst.map' or 'inst_maps:::myfile,map'
• this will add a detector map file location to an IXTdata_source object