message: Have Tile::distanceTo original method delegate to new method
  This reduces code repetition, and means only one implementation needs to
  be maintained.
diff: @@ -127,9 +127,7 @@ Robot* Tile::robot()
  */
  float Tile::distanceTo(Tile* t)
  {
  - int x = t->x() - Tile::x();
  - int y = t->y() - Tile::y();
  - return static_cast<float>(sqrt((x * x) + (y * y)));
  + return distanceTo(t->position());
  }
  