Issue #37 GUI message when FPS drops below threshold

src/blackgui/components/loginadvcomponent.h

@@ -127,6 +127,9 @@ namespace BlackGui
             //! Auto-logoff detection
             void autoLogoffDetection();
 
+            //! Logoff due to insufficient simulator frame rate
+            void autoLogoffFrameRate(bool fatal);
+
             //! Pause/Continue timeout
             void toggleTimeout();