Fix config.json and add favicon support

/to @bajtos or @ritch 

The PR fixes 3 issues:
- Make sure the app is listening on 0.0.0.0:3000 instead of localhost:3000
- Add favicon middleware to avoid 404 warnings
- Fixes https://github.com/strongloop/generator-loopback/issues/12
The favicon middleware is usually at the top of the middleware chain, often before the logging middleware. Please move it to the top.

Add a unit-test to `test/end-to-end.js` to verify that the favicon does not return 404.