message: Use dictionaryToAttributes to write mine vein data
diff: @@ -311,13 +311,16 @@ NAS2D::Xml::XmlElement* Mine::serialize(NAS2D::Point<int> location)
  {
  const MineVein& mv = mVeins[i];
  - XmlElement* vein = new XmlElement("vein");
  -
  - vein->attribute("id", static_cast<int>(i));
  - vein->attribute("common_metals", mv[OreType::ORE_COMMON_METALS]);
  - vein->attribute("common_minerals", mv[OreType::ORE_COMMON_MINERALS]);
  - vein->attribute("rare_metals", mv[OreType::ORE_RARE_METALS]);
  - vein->attribute("rare_minerals", mv[OreType::ORE_RARE_MINERALS]);
  + auto* vein = NAS2D::dictionaryToAttributes(
  + "vein",
  + {{
  + {"id", static_cast<int>(i)},
  + {"common_metals", mv[OreType::ORE_COMMON_METALS]},
  + {"common_minerals", mv[OreType::ORE_COMMON_MINERALS]},
  + {"rare_metals", mv[OreType::ORE_RARE_METALS]},
  + {"rare_minerals", mv[OreType::ORE_RARE_MINERALS]},
  + }}
  + );
  element->linkEndChild(vein);
  }
  