Add support for codec engine for sending message from worker to broker

[Shankar-khati]

scc-broker-client/client-pool.js

Line 46 in 3b6af62

let client = socketClusterClient.create(connectOptions);

Here i don't see the way to add a codec engine where i can compress the message.

Problem:
I have added custom codec engine to compress data from client to worker and when worker sends that message to brokers it's again decompressed form which throws an error "Message is too large to process".

Solution:
We can provide option to add codec engine here:

scc-broker-client/client-pool.js

Line 46 in 3b6af62

let client = socketClusterClient.create(connectOptions);

So that we can send message from worker to broker in compressed form

we can provide coded engine option from here
https://github.com/SocketCluster/socketcluster/blob/7b1d97cbcd9d37ae51eb9305bbaedfac774622b8/app/server.js#L99-L113
@jondubois please let us know your thoughts on the same

[BLineBrian]

I just put in a PR for this: #11

You'll also need to specify a codec on the broker itself.