express.listen() should return http.Server

In express 3.x, express no longer inherits from http.Server.  Instead, express.listen() should return an http.Server object that you can use to get the current port or stop the express server, for example.

I found the node definitions were also incorrect.  The .listen() and .close() methods should return a Server object, and the http.Server should have an address() definition.

This patch makes the appropriate updates to both the node and express definitions.