WCF (Websocket Communication Foundation) - a skeleton for websocket transport

I originally had this idea to not use `using namespace` for external dependencies. However I agree that the way it looks in case of websockets I just horrible. I am thinking about going halfway by doing 'using namespace web::experimental' which will result in `web_sockets::client::{type}` - a more sane thing. 

The implementation is in the header file because of the template.