reworked coodinate system

Demo:
-removed clicked_waypoint
-removed initialisation from start()
-removed selected_path_point
-removed initialisation from start()
-removed compassClicked()

GameWindow:
-added clickedWaypoint
-added selectedPathPoint
-reworked isArrivalsClicked()
+expects coordinates corrected to be part of the game area
-reworked isDeparturesClicked()
+expects coordinates corrected to be part of the game area
-reworked compassClicked()
+expects coordinates corrected to be part of the game area