message: add Display instance for Addressing
diff: @@ -254,6 +254,11 @@ pub struct Addressing {
  pub change: u32,
  pub index: Index,
  }
  +impl fmt::Display for Addressing {
  + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  + write!(f, "{}.{}.{}", self.account.0, self.change, self.index.0)
  + }
  +}
  #[derive(Clone, Copy, Serialize, Deserialize, Debug, PartialEq, Eq)]
  pub enum AddrType {
  