message: Combine other Mine fields into same Dictionary as location
diff: @@ -299,15 +299,14 @@ NAS2D::Xml::XmlElement* Mine::serialize(NAS2D::Point<int> location)
  "mine",
  {{
  {"x", location.x},
  - {"y", location.y}
  + {"y", location.y},
  + {"depth", depth()},
  + {"active", active()},
  + {"yield", static_cast<int>(productionRate())},
  + {"flags", mFlags.to_string()},
  }}
  );
  - element->attribute("depth", depth());
  - element->attribute("active", active());
  - element->attribute("yield", static_cast<int>(productionRate()));
  - element->attribute("flags", mFlags.to_string());
  -
  for (std::size_t i = 0; i < mVeins.size(); ++i)
  {
  const MineVein& mv = mVeins[i];
  