Remove mreg.asc and all gdc files from CS-Map

[hugueswski]

Since the implementation of RFC2, the GDC and MRT files have become obsolete and unused by CS-Map. We need to remove the mreg.asc source file that is used to output all *.MRT multiple regression output files. We also need to remove all the *.gdc files since now the grid files order is directly handled by GeodeticTransformation.asc and its binary forn GeodeticTransformation.csd This is not really a defect or enhancement. It's more like a cleanup activity.