message: Delay clearing `mPlanetAttributes` in `MapViewState::load`
  Don't clear it until we are ready to set new values.
  This helps highlight that not all `Planet::Attributes` fields are set
  when loading a map.
diff: @@ -141,7 +141,6 @@ NAS2D::Xml::XmlElement* MapViewState::serializeProperties()
  void MapViewState::load(const std::string& filePath)
  {
  - mPlanetAttributes = Planet::Attributes();
  resetUi();
  auto& renderer = NAS2D::Utility<NAS2D::Renderer>::get();
  @@ -172,6 +171,7 @@ void MapViewState::load(const std::string& filePath)
  NAS2D::Xml::XmlElement* map = root->firstChildElement("properties");
  const auto dictionary = NAS2D::attributesToDictionary(*map);
  + mPlanetAttributes = Planet::Attributes();
  mPlanetAttributes.maxDepth = dictionary.get<int>("diggingdepth");
  mPlanetAttributes.mapImagePath = dictionary.get("sitemap");
  mPlanetAttributes.tilesetPath = dictionary.get("tset");
  