like "fully trusted", "marginally trusted", etc. (get_min_ownertrust):
New. Return minimum ownertrust. (update_min_ownertrust): New. Set
minimum ownertrust. (check_regexp): New. Check a regular epression
against a user ID. (ask_ownertrust): Allow specifying a minimum value.
(get_ownertrust_info): Follow the minimum ownertrust when returning a
letter. (clear_validity): Remove minimum ownertrust when a key becomes
invalid. (release_key_items): Release regexp along with the rest of the
info. (validate_one_keyblock, validate_keys): Build a trust sig chain
while validating. Call check_regexp for regexps. Use the minimum
ownertrust if the user does not specify a genuine ownertrust.
* pkclist.c (do_edit_ownertrust): Only allow user to select a trust level
greater than the minimum value.
* parse-packet.c (can_handle_critical): Can handle critical trust and
regexp subpackets.
* trustdb.h, trustdb.c (clear_ownertrusts), delkey.c (do_delete_key),
import.c (import_one): Rename clear_ownertrust to clear_ownertrusts and
have it clear the min_ownertrust value as well.
* keylist.c (list_keyblock_print): Indent uid to match pub and sig.
menu_addrevoker), keylist.c (list_keyblock_print, print_fingerprint): Show
"T" or the trust depth for trust signatures, and add spaces to some
strings to make room for it.
* packet.h, parse-packet.c (dump_sig_subpkt, parse_one_sig_subpkt,
parse_signature): Parse trust signature values.
* tdbio.h, tdbio.c (tdbio_read_record, tdbio_write_record): Reserve a byte
for the minimum ownertrust value (for use with trust signatures).
that fact in the capabilities, and only primary signing keys can certify
other keys.
* packet.h, parse_packet.c (parse_key): Add is_primary flag for public
keys (it already exists for secret keys).