Multiple things (read description below)

- Fix minor issue with the relation of public keys
- Delete the commands set-gpg-id and remove-gpg-id
- Add command remove-public-key (issue #50)
- Update autocompletion
- change some names especially request-key in request-public-key

Signed-off-by: Sven Haardiek <Sven@Haardiek.de>