Modified Map.h:
    vector<City> worldMap;  --->  vector<City*> worldMap;

modified Map.cpp:
    City Map::locateCity(string cityName)  ---> City* Map::locateCity(string cityName)

Because City objects are now pointers,
I changed method calls from "." to "->":

		worldMap[i].getCityName() == cityName --->
    worldMap[i]->getCityName() == cityName

I found this issue out when trying to move a player from one city to
other.  There was a conflict with one method return a non-pointer in
order to assign to a pointer.