Check advanced mode

[wiegelmann]

Advanced mode give output in "Validate OpenPGP Public Key", but not "Validate OpenPGP Message" and does not change message from "message" to the encrypted message. Would be nice if you could notify user when it fails to generate a PGP message. I suggest checking if the encrypted message is empty or if it contains "BEGIN PGP MESSAGE" before sending it and before telling user that it succeeded.