title: tornado 403 GET warning when opening websocket
body: <p>I found this python script which should allow me to open a WebSocket.
  However, I receive the warning <code>[W 1402720 14:44:35 web:1811] 403 GET / (192.168.0.102) 11.02 ms</code> in my Linux terminal when trying to open the actual WebSocket (using Old WebSocket Terminal Chrome plugin). The messages "connection opened", "connection closed" and "message received" are never printed in the terminal window. </p>
  
  <pre><code>import tornado.httpserver
  import tornado.ioloop
  import tornado.options
  import tornado.web
  import tornado.websocket
  
  class MyHandler(tornado.websocket.WebSocketHandler):
          def open(self):
                  print "connection opened"
                  self.write_message("connection opened")
  
          def on_close(self):
                  print "connection closed"
  
          def on_message(self,message):
                  print "Message received: {}".format(message)
                  self.write_message("message received")
  
  if __name__ == "__main__":
          tornado.options.parse_command_line()
          app = tornado.web.Application(handlers=[(r"/",MyHandler)])
          server = tornado.httpserver.HTTPServer(app)
          server.listen(8888)
          tornado.ioloop.IOLoop.instance().start()
  </code></pre>