THRIFT-2819 - Add WebsSocket client to node.js 

I needed a WebSocket client for node.js and implemented it.
I am sharing my code with the community:

This PR adds a WebSocket client to the node.js library.
It is a combination of http_connection.js and the WebSocket implementation from js.
Adds dependency to https://github.com/einaros/ws
Includes integration tests.
Works with browserify.

It only works with TJSONProtocol and TBufferedTransport because sending raw binary data on a WebSocket currently causes an UTF8 error.
Maybe it is possible to fix?

EDIT: binary support is now included