Made changes to support express v4 in sample code.

This involved some simple changes:
 * removing the logger call and replacing that with morgan.
 * removing the createServer() and just setting express() as the call.
 * placement of the app.use statements for morgan and passport.initialize() above the app.get routing but before other declarations.

Hey @jaredhanson if that PR is cool, I can update the other samples too (the digest sample, etc) and add them to the PR if you'd like or submit separate ones. I was going to try and go through and update any that I could find time to. Cheers!