cli argument to load an rfc

[jayvdb]

https://github.com/lewiseason/rfc/blob/master/rfc/cli.py allows a CLI arg for the rfc number to jump straight to the reader.

https://github.com/monsieurh/rfc_reader also does, and has several other CLI args.

RFC.py conflicts with both of those Python packages, as they all install cli command rfc

In other langs https://github.com/jwerle/rfc and https://github.com/pissedoffadmins/rfc-reader also allow opening an rfc from the CLI.

[danielmichaels]

I think this is a great enhancement and time saver for commonly opened rfc's.

It doesn't matter that those other packages use the rfc namespace - this would need to be written into this project anyway. Injecting an rfc number into the app shouldn't be too hard.

Any contributions here are welcome.