-h should be an alias for --help

[jyn514]

--help takes too long to type :(

$ bacon -h
Unrecognized argument: -h

[Canop]

I'm careful with that because it means -h can't be used for something else. It's still undecided.

[Canop]

I've decided for this shortcut but Argh doesn't support it today (this PR is pending). I don't want to replace Argh for just this small change so I'll wait for the PR to be merged or refused.