Fix an example to prevent a warning about express

[gologo13]

I found the following warning when I started an example of this library.
I prevented this warning by this pull request.

$ node app
Warning: express.createServer() is deprecated, express
applications no longer inherit from http.Server,
             please use:

              var express = require("express");
              var app = express();

[tmcw]

@jaredhanson ping - this looks to be pretty straightforward and anyone npm install'ing the examples will install a recent version of express

[jaredhanson]

Merged, thanks! Most of the examples were written in the Express 2.x days, so they suffer this particular deprecation.