Fixed infinity-loop on simulation end

src/de/tud/kom/p2psim/impl/topology/movement/VehicleMovementModel.java

@@ -279,7 +279,9 @@ public class VehicleMovementModel implements MovementModel, EventHandler, Future
 		long currentTime = Time.getCurrentTime() / timestepConversion;
 
 		while (_controller.getStep() - _controller.getStart() < currentTime) {
-			_controller.nextStep();
+			if (!_controller.nextStep()) {
+				return;
+			}
 		}
 
 		List<String> allVehicles = _controller.getAllVehicles();