message: Use single stage construction of MineVein when loading from file
diff: @@ -303,11 +303,12 @@ void Mine::deserialize(NAS2D::Xml::XmlElement* element)
  {
  const auto veinDictionary = NAS2D::attributesToDictionary(*vein);
  - MineVein mineVein{0, 0, 0, 0};
  - mineVein[OreType::ORE_COMMON_METALS] = veinDictionary.get<int>("common_metals");
  - mineVein[OreType::ORE_COMMON_MINERALS] = veinDictionary.get<int>("common_minerals");
  - mineVein[OreType::ORE_RARE_METALS] = veinDictionary.get<int>("rare_metals");
  - mineVein[OreType::ORE_RARE_MINERALS] = veinDictionary.get<int>("rare_minerals");
  + MineVein mineVein{
  + veinDictionary.get<int>("common_metals", 0),
  + veinDictionary.get<int>("common_minerals", 0),
  + veinDictionary.get<int>("rare_metals", 0),
  + veinDictionary.get<int>("rare_minerals", 0),
  + };
  mVeins.push_back(mineVein);
  }
  