gpg: Start using OpenPGP digest algo ids.
* g10/misc.c (print_pubkey_algo_note): Use enum typedef for the arg. (print_cipher_algo_note): Ditto. (print_digest_algo_note): Ditto. (map_md_openpgp_to_gcry): New. (openpgp_md_test_algo): Rewrite. (openpgp_md_algo_name): Rewrite to do without Libgcrypt. * g10/cpr.c (write_status_begin_signing): Remove hardwired list of algo ranges.