Created by: GertSallaerts
A "light" alternative to https://github.com/nodejitsu/node-http-proxy/pull/991. This simply allows us to pass in two options: createWsClientTransformStream and/or createWsServerTransformStream. Implementation of parsing and/or transforming the messages is left up to the user.
It's also a solution to https://github.com/nodejitsu/node-http-proxy/issues/1203