Fixed another very subtle race condition. This hopefully gets all green on the CI.

Also the test runner now observes BOOST_AFIO_NEED_CURRENT_EXCEPTION_HACK, and I turned BOOST_AFIO_NEED_CURRENT_EXCEPTION_HACK on for all older C++ 11 compilers rather than just VS2010.
Fixed the TabsToSpaces script not fixing up .ipp files.