MINIFICPP-1096 appveyor ctest output-on-failure
MINIFICPP-1096 appveyor ctest output-on-failure

Signed-off-by: Arpad Boda <aboda@apache.org>

This closes #756

achristianson/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,achristianson/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,apiri/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp,apiri/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,achristianson/nifi-minifi-cpp,achristianson/nifi-minifi-cpp,apiri/nifi-minifi-cpp,apiri/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,jdye64/nifi-minifi-cpp,apiri/nifi-minifi-cpp,dtrodrigues/nifi-minifi-cpp