message: Set ROBOT_ID_COUNTER to max loaded value over all robots
  This eliminates most potential problems with malformed saved game files.
  It also eliminates the need to write the value to the saved game file.
diff: @@ -261,11 +261,7 @@ void MapViewState::readRobots(Xml::XmlElement* element)
  mRobotList.clear();
  mRobots.dropAllItems();
  - /**
  - * \fixme This is fragile and prone to break if the savegame file is malformed.
  - */
  - element->firstAttribute()->queryIntValue(ROBOT_ID_COUNTER);
  -
  + ROBOT_ID_COUNTER = 0;
  int id = 0, type = 0, age = 0, production_time = 0, x = 0, y = 0, depth = 0, direction = 0;
  XmlAttribute* attribute = nullptr;
  for (XmlNode* robotNode = element->firstChild(); robotNode; robotNode = robotNode->nextSibling())
  @@ -285,6 +281,7 @@ void MapViewState::readRobots(Xml::XmlElement* element)
  attribute = attribute->next();
  }
  + ROBOT_ID_COUNTER = std::max(ROBOT_ID_COUNTER, id);
  Robot* robot = nullptr;
  switch (static_cast<RobotType>(type))
  