add main


add class StartGame with main-method
The main-method creates a dummy map and prints it on the console
add class MapCoordinates


add class that contains public integers for x, y and z to group
coordinates and reduce the need to give the values in a specific order
add/edit some comments
add constructor with default vales for MapCoordinates
use MapCoordinates in Map and StartGame

use MapCoordinates instead of three integer values to transmit
coordinates