Minor improvements

Thanks for your efforts regarding keybase! I just started using it a bit more, and found a few minor, but annoying things:
- Add a newline after exiting the keybase command line app (e.g. after displaying the results of an encrypted message)
-----END PGP MESSAGE-----user@host:~$
- `keybase help pgp` doesn't show the valid arguments for a command, e.g. I would like to know more about the pgp encrypt command, but `keybase help pgp encrypt` doesn't show anything useful

Start by reproducing the output from the keybase command line app, then inspect the behavior of `keybase help pgp` and `keybase help pgp encrypt`. Done means encrypted-message output ends with a newline and the help commands describe the valid arguments for the relevant command.

Written by the indexing model from the issue text.