Simple WebSockets for subscriptions

[wsobel]

Implement a simple WebSockets streaming service. This is long overdue and can replace our long-poll version.

We can use a simple JSON subscription request to stream data once the connection opens. I will take some recommendations here.

[wsobel]

The first version of this is released in Version 2.5.0.0 RC 2.

[wsobel]

Completed in 2.5.

[wsobel]

Finished initial implemenetation