message: fixed wrong parameter (features=unstable)
diff: @@ -224,7 +224,7 @@ mod tests {
  let mut encrypted = vec![];
  let e = Encryptor::Keys(vec![pk]);
  {
  - let mut w = e.wrap_output(&mut encrypted, false).unwrap();
  + let mut w = e.wrap_output(&mut encrypted, Format::Binary).unwrap();
  w.write_all(test_msg).unwrap();
  w.finish().unwrap();
  }
  