terminate when balance server is not reachable

gamemenu.py

@@ -200,6 +200,7 @@ class BalanceInput(AbstractInput, threading.Thread):
         self.evt = None
         self.lastevt = None
         self.player_present = False
+        self.running = False
         threading.Thread.__init__(self, daemon=True)
         self.start()
 
@@ -272,7 +273,8 @@ class BalanceInput(AbstractInput, threading.Thread):
 
     def get_event(self):
         evt = self.evt
-        self.evt = None
+        if self.running:
+            self.evt = None
         return evt
 
 def start_game(game, players):