publish subscribes and connected-client

[mocheng]

Fix #92

Publish new client by default would break a lot of unit test cases. So, I add one server.options named publishNewClient to switch the feature, which is off by default.

[mcollina]

broker-id should be built on the broker's id :).

[mocheng]

You are right.
Do you prefer to having the published message only client id in string, or having it a JSON {clientId: xxxxx}?

[mcollina]

I prefer the client id in the string. However you may leave that in the JSON too, it does not harm.

[mcollina]

Good one! Do you think it's ready for merging and releasing?
I would love to release it today as 0.24.0 (I also bumped some dependencies on master).

[mocheng]

We've deployed this change in our test environment today. There is no issue yet. It should work well.

Just not sure whether new published message would burden backend ascoltatori. In our env, about 10 connect/subscribe per second works well.

[mcollina]

I think you intended 'new subscribe' message.

What do you think about changing the default of publishNewClient to true (and setting it off in the settings for tests https://github.com/mcollina/mosca/blob/master/test/server.js#L7-L19). This is needed to make Redis, MongoDB and AMQP things MQTT-compliant.

[mocheng]

That should be good.
Default on would make this feature well exposed to more users.
I'll update it.

[mocheng]

Turn publishNewClient on by default. Several test files are updated to turn off publishNewClient in unit testing.

[mcollina]

Released as 0.24.0.