Would like way to discover commands in `helios-build`

[rmustacc]

I tried to discover the various commands that helios-build supports by either passing help, or -h, but none of these actually provide a way to find something. It would help if there was a useful way to get this out. If you use no options it does work, but maybe having help be an alias would be nice. I'm not sure why the other day I didn't run it with no options, but that might be just from a history of being uncertain what a program will do.