Close connection after Websocket handshake

Otherwise we might misinterpret trailing binary data as a second
HTTP request. This happens when we return from the handler with
data still queued up in the socket.

websockify/websocket.py

@@ -467,6 +467,10 @@ def do_websocket_handshake(self):
             else:
                 self.send_header("Sec-WebSocket-Protocol", "binary")
             self.end_headers()
+
+            # Other requests cannot follow Websocket data
+            self.close_connection = True
+
             return True
         else:
             self.send_error(400, "Missing Sec-WebSocket-Version header. Hixie protocols not supported.")