message: Added default ignore behaviour for macros.
  Now ignore unimplemented and unreachable macro invocations as these should never occur and if they do they cause the program to panic.
diff: @@ -109,7 +109,12 @@ impl<'v, 'a> Visitor<'v> for IgnoredLines<'a> {
  fn visit_mac(&mut self, mac: &Mac) {
  // Use this to ignore unreachable lines
  -
  + let mac_text = &format!("{}", mac.node.path)[..];
  + match mac_text {
  + "unimplemented" => self.ignore_lines(mac.span),
  + "unreachable" => self.ignore_lines(mac.span),
  + _ => {},
  + }
  visit::walk_mac(self, mac);
  }
  