message: Update maintenance facility & write integrity value to save games
diff: @@ -63,6 +63,7 @@ void StructureManager::update(const StorableResources& resources, PopulationPool
  updateStructures(resources, population, mStructureLists[Structure::StructureClass::Nursery]);
  updateStructures(resources, population, mStructureLists[Structure::StructureClass::Factory]); // Production
  + updateStructures(resources, population, mStructureLists[Structure::StructureClass::Maintenance]);
  updateStructures(resources, population, mStructureLists[Structure::StructureClass::Storage]); // Everything else.
  updateStructures(resources, population, mStructureLists[Structure::StructureClass::Park]);
  @@ -406,6 +407,7 @@ void serializeStructure(NAS2D::Xml::XmlElement* structureElement, Structure* str
  structureElement->attribute("idle_reason", static_cast<int>(structure->idleReason()));
  structureElement->attribute("type", structure->structureId());
  structureElement->attribute("direction", structure->connectorDirection());
  + structureElement->attribute("integrity", structure->integrity());
  if (structure->hasCrime())
  {
  