g10.c (main): add new --export-options option. Current flags are
"include-non-rfc", "include-local-sigs", "include-attributes", and
"include-sensitive-revkeys".
* options.h, hkp.c (hkp_export), keyserver.c (parse_keyserver_options,
keyserver_spawn): try passing unknown keyserver options to export options,
and if successful, use them when doing a keyserver --send-key.
* build-packet.c (build_sig_subpkt): We do not generate
SIGSUBPKT_PRIV_VERIFY_CACHE anymore.
designated revoker means "sensitive", not "local". It's exportable under
the right circumstances.
* main.h, options.h, export.c (do_export_stream), g10.c (main), hkp.c
(hkp_export), keyserver.c (keyserver_spawn: Add a flag to skip attribute
packets and their signatures while exporting. This is to accomodate
keyservers (pksd again) that choke on attributes. Use keyserver-option
"include-attributes" to control it. This defaults to ON (i.e. don't
skip).
