card: New command "apdu"

* tools/card-call-scd.c (scd_apdu): Add optional arg 'options'.
* tools/gpg-card.c (cmd_apdu): New.
(enum cmdids): Add cmdAPDU.
(dispatch_command): Add command "apdu".
(interactive_loop): Ditto.

This command is hidden because it can be used to brick a card. The
command is basically the same as sending "scd apdu" in
gpg-connect-agent but here we do full decoding and printing in hex.

• Signed-off-by: Werner Koch <wk@gnupg.org>