alarm image persist for 1 second longer

pi/.gitignore

@@ -5,5 +5,5 @@ __pycache__/
 *.pyc
 
 # configs
-./configs/
-!configs/alarms.sample.json
+config/
+!config/alarms.sample.json

pi/contents_server.py

@@ -93,6 +93,8 @@ async def handler(ws):
                         await send_status_image(ws, current_img)
                         await stream_alarm(ws, alarm["pcm"], alarm["sr"],
                                            alarm["ch"], alarm["bits"])
+                        # let the image persist a bit more
+                        await asyncio.sleep(1)
                         current_img = img_idle
                         await send_status_image(ws, current_img)