+add utf-8 validation code, not hooked up properly yet

+ws autobahn / Add code to test websocket client compliance with the autobahn test-suite
+Ping received with a payload too large (> 125 bytes) trigger a connection closure
+cobra / add tracking about published messages
+cobra / publish returns a message id, that can be used when
+cobra / new message type in the message received handler when publish/ok is received (can be used to implement an ack system).

DOCKER_VERSION

@@ -1 +1 @@
-5.0.7
+5.1.0