revised the mod2cs, fixing a serious bug that assumed a predefine sequence of d/o; in the load method, added the "force" option and fixed a bug when there is no model error in the data file; implemented the ggm05g method; added path to yaml utilities in the load_gsm method
revised the mod2cs, fixing a serious bug that assumed a predefine sequence of d/o; in the load method, added the "force" option and fixed a bug when there is no model error in the data file; implemented the ggm05g method; added path to yaml utilities in the load_gsm method

jgte/orb,jgte/orb,jgte/orb,jgte/orb,jgte/orb