* scd/app-openpgp.c (KEY_TYPE_EDDSA, CURVE_ED25519): New.
(struct app_local_s): Add eddsa.
(get_algo_byte, store_fpr): Support KEY_TYPE_EDDSA.
(get_ecc_key_parameters, get_curve_name): Support CURVE_ED25519.
(send_key_attr, get_public_key): Support KEY_TYPE_EDDSA.
(build_ecc_privkey_template): Rename as it supports both of
ECDSA and EdDSA.
(ecc_writekey): Rename.  Support CURVE_ED25519, too.
(do_writekey): Follow the change of ecc_writekey.
(do_auth): Support KEY_TYPE_EDDSA.
(parse_ecc_curve): Support CURVE_ED25519.  Bug fix for other curves.
(parse_algorithm_attribute): Bug fix for ECDH.  Support EdDSA.