Play finishes after one episode resulting in an broken pipe.

Not shure if the animation should be endless, but an error is wrong and the server part was written to do more than 1 episode.
#8

agent_zoo/demo_pong.py

@@ -37,5 +37,6 @@ def play(env, pi, video):
         pi = Pol1(env.observation_space, env.action_space)
     else:
         pi = Pol2(env.observation_space, env.action_space)
-    play(env, pi, video=False)   # set video = player_n==0 to record video
+    while True:
+        play(env, pi, video=False)   # set video = player_n==0 to record video