Run cmparseMSBuildXML.py on cl.xml, lib.xml, link.xml, and masm.xml to
generate our flag tables:

 python cmparseMSBuildXML.py -x ".../Common7/IDE/VC/VCTargets/1033/cl.xml" > cmVS14CLFlagTable.h
 python cmparseMSBuildXML.py -x ".../Common7/IDE/VC/VCTargets/1033/lib.xml" > cmVS14LibFlagTable.h
 python cmparseMSBuildXML.py -x ".../Common7/IDE/VC/VCTargets/1033/link.xml" > cmVS14LinkFlagTable.h
 python cmparseMSBuildXML.py -x ".../Common7/IDE/VC/VCTargets/BuildCustomizations/masm.xml" > cmVS14MASMFlagTable.h

Manually integrate the changes with those we've made since earlier
import to add the new flag mappings.