Broke off the tankIter Initialization

bool PrototypeState::Enter()
{
    state_window = ServiceLocator<Window>::get_service();
    game_world = GameWorld::create();
    game_world->Initialize();
    game_world->TankStateEnter(sf::Vector2f(HALFTILEWIDTH + 1 * TILEWIDTH, HALFTILEHEIGHT + 18 * TILEHEIGHT), RED);
    game_world->TankStateEnter(sf::Vector2f(HALFTILEWIDTH + 18 * TILEWIDTH, HALFTILEHEIGHT + 1 * TILEHEIGHT), GREEN);

    game_world->SetTankIterator();//<-------------------------------------THE NEW FUNCTION, DEF BELLOW.

    ServiceLocator<GameWorld>::set_service(game_world);

    graph = ServiceLocator<Graph>::get_service();

    BlackBoard<GameWorld>* black = new BlackBoard<GameWorld>;
    black->Start();
    ServiceLocator<BlackBoard<GameWorld>>::set_service(black);


    BTree = new bt1::FirstBTFindBase;
    bt1::ConditionArrived<GameWorld>* condition1 = new bt1::ConditionArrived<GameWorld>;
    bt1::ConditionBaseWalkable<GameWorld>* condition2 = new bt1::ConditionBaseWalkable<GameWorld>;
    bt1::ActionFindPathAndGo<GameWorld>* action1 = new bt1::ActionFindPathAndGo<GameWorld>;
    bt1::ActionSetArrived<GameWorld>* action2 = new bt1::ActionSetArrived<GameWorld>;
    BTree->SearchBaseAndGo->addChild(condition1);
    BTree->SearchBaseAndGo->addChild(condition2);
    BTree->SearchBaseAndGo->addChild(action1);
    BTree->SearchBaseAndGo->addChild(action2);

    ServiceLocator<bt1::FirstBTFindBase>::set_service(BTree);

    return true;
}

void GameWorld::SetTankIterator()
{
    tankIter = tanks.begin();
}