display: improve shutdown message

scripts/planktoscope/display.py

@@ -100,6 +100,7 @@ class Display(object):
 
     def stop(self):
         logger.info("Display is out!")
+        self.display_text("Shutdown in 5s")
         self.__clear()
 
 
@@ -112,4 +113,4 @@ if __name__ == "__main__":
     time.sleep(5)
     display.display_text("Bye!")
     time.sleep(5)
-    display.stop()
+    display.stop()