reverse Android subscribeToChannel params

[ggendre]

Reverse arguments to be able to write this :

Cobalt.subscribeToChannel("myChannel", new PubSubInterface() {
        @Override
        public void onMessageReceived(@Nullable JSONObject message, @NonNull String channel) {
            Log.d("hop", "myChannel message received");            
        }
    });

instead of this :

Cobalt.subscribeToChannel(new PubSubInterface() {
        @Override
        public void onMessageReceived(@Nullable JSONObject message, @NonNull String channel) {
            Log.d("hop", "myChannel message received");            
        }
    }, "myChannel");

and update samples accordingly