renamig vehicle group in results for primary bus to PrimaryVehicleSubgroup

correcting typo in xml type name,
adapting xample XML files, testfiles
always write retarder (where possible), only write retarder type in MRF, VIF contains info about retarder (manufacturer, model, ...)
writing values in correct units (IEPC, EM) to MRF, VIF
adding certification method to battery, supercap, EM,
removing busaux pneumatic system elements for PEV, correcting output for pneumatic system technology PEV,
adding type info in schema
correcting results: no CO2 in VIF results, average passenger count in CIF summary