message: Remove obsolete code to generate unique IDs using sentinel value
  At this point, a unique ID will already be generated, so use the passed
  value. At least, assuming no code is explicitly passing a sentinel value
  to indicate it wants to a new ID generate.
diff: @@ -67,27 +67,23 @@ Robot* RobotPool::addRobot(Robot::Type type)
  */
  Robot* RobotPool::addRobot(Robot::Type type, int id)
  {
  - int _id = 0;
  - if (id == 0) { _id = ++ROBOT_ID_COUNTER; }
  - else { _id = id; }
  -
  switch (type)
  {
  case Robot::Type::Dozer:
  mDozers.push_back(new Robodozer());
  - mDozers.back()->id(_id);
  + mDozers.back()->id(id);
  mRobots.push_back(mDozers.back());
  return mDozers.back();
  case Robot::Type::Digger:
  mDiggers.push_back(new Robodigger());
  - mDiggers.back()->id(_id);
  + mDiggers.back()->id(id);
  mRobots.push_back(mDiggers.back());
  return mDiggers.back();
  case Robot::Type::Miner:
  mMiners.push_back(new Robominer());
  - mMiners.back()->id(_id);
  + mMiners.back()->id(id);
  mRobots.push_back(mMiners.back());
  return mMiners.back();
  