Fixed so that 'add_unit_test' (./cmake/testing.cmake) applies same cpp-standards as parent target (eg. CXX_STANDARD=C++17 etc.), so that if parent uses C++17 features, the test-target can as well.
Fixed so that 'add_unit_test' (./cmake/testing.cmake) applies same cpp-standards as parent target (eg. CXX_STANDARD=C++17 etc.),
so that if parent uses C++17 features, the test-target can as well.

helmesjo/hello-cd,helmesjo/hello-cd