Add --version command for testing

[Pandapip1]

Hi! I'm in the middle of refactoring the direwolf package build file for NixOS, and noticed that there isn't a --version or similar command that produces a minimal output that can be used to check that everything built and runs as expected. Would you consider adding one?

[Pandapip1]

Actually, it looks like the -u option works for our use-case.