Added displaying timestamp for new optimal router

Graph.cpp

                 globalOptimumLength = nextRouteLength;
                 globalOptimum = nextRoute;
 
-                std::cout << "Nowa najlepsza trasa: " << globalOptimumLength << std::endl;
+                onboardClock.stop();
+                std::cout << "Nowa najlepsza trasa: " << globalOptimumLength;
+                std::cout << " (w czasie " << onboardClock.read() << " s)" << std::endl;
             }
             globalOptimumMutex.unlock();