Tests fail if building inside of source

[cwschilly]

If you have your build directory as a subdirectory of the pressio-tutorials repo (not encouraged, but not the end of the world), the tests all fail because of a safeguard in the Python scripts to make sure they're being called from the build directory:

  if is_git_repo(workDirFullPath):
    print("you cannot run this script from the tutorials repo!")
    sys.exit(23)

This is_git_repo check is too strong. We should find a different way to confirm that we're in the build directory.