Add secp256k1 curve.
* cipher/ecc-curves.c (curve_aliases): Add secp256k1 and its OID. (domain_parms): Add secp256k1's domain paramerter. * tests/basic.c (check_pubkey): Add a key of secp256k1. * tests/curves.c (N_CURVES): Updated.
The key in check_pubkey is from "Test vector 1" of following page.
https://en.bitcoin.it/wiki/BIP_0032_TestVectors
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>