websocket support

[linsong]

WebSocket can make data communication between sedona and HTTP client(event non HTTP client) faster, that will make dashboard like application to present sedona data on UI and send control command to sedona side faster and easier.

In this ticket, we just make general websocket to work, but not implement the application level logics. You can think of this as Dasp, and the application level logics as Sox. We do the Dasp part first here, and do the Sox part later.

Some resource:

• Writing WebSocket Servers
• The WebSocket Protocol