crypto: merge Cipher and Decipher
crypto: refactor Hmac
crypto: refactor Hash
crypto: refactor Sign
crypto: refactor Verify
crypto: replace BIO_free with BIO_free_all
crypto: fix nits in CipherBase
crypto: fix some nits in Hmac
crypto: another CipherBase nits
crypto: fix nits in Hash
crypto: fix nits in Sign
crypto: fix nits in Verify
crypto: refactor diffie-hellman