message: refactor(http): add status() methods to RawStatus and ResponseHead
  This lets us convert RawStatus to StatusCode in Response without having to address the tuple index
  directly.
diff: @@ -71,10 +71,26 @@ impl<S> MessageHead<S> {
  }
  }
  +impl ResponseHead {
  + /// Converts this head's RawStatus into a StatusCode.
  + #[inline]
  + pub fn status(&self) -> StatusCode {
  + self.subject.status()
  + }
  +}
  +
  /// The raw status code and reason-phrase.
  #[derive(Clone, PartialEq, Debug)]
  pub struct RawStatus(pub u16, pub Cow<'static, str>);
  +impl RawStatus {
  + /// Converts this into a StatusCode.
  + #[inline]
  + pub fn status(&self) -> StatusCode {
  + StatusCode::from_u16(self.0)
  + }
  +}
  +
  impl fmt::Display for RawStatus {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  write!(f, "{} {}", self.0, self.1)
  