Look for the "/threads", "/libs:dll", and "/dbglibs" flags and convert
them to the proper RuntimeLibrary attribute value in the IDE. This is
a 3-to-1 flag mapping and such needs special handling in the parser.
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.