message: Change signature verification equation to permit batch verification.
diff: @@ -145,8 +145,11 @@ impl<E: JubjubEngine> PublicKey<E> {
  Ok(s) => s,
  Err(_) => return false,
  };
  - // S . P_G = R + c . vk
  - self.0.mul(c, params).add(&r, params) == params.generator(p_g).mul(s, params).into()
  + // 0 = 8(-S . P_G + R + c . vk)
  + self.0.mul(c, params).add(&r, params).add(
  + &params.generator(p_g).mul(s, params).negate().into(),
  + params
  + ).mul_by_cofactor(params).eq(&Point::zero())
  }
  }
  