* g10/gpg.c (oKnownNotation): New const.
(opts): Add option --known-notation.
(main): Set option.
* g10/parse-packet.c (known_notations_list): New local var.
(register_known_notation): New.
(can_handle_critical_notation): Rewrite to handle the new feature.
Also print the name of unknown notations in verbose mode.