Use Java 8 syntax in the example application

I'm not sure what the intention is with this example app (in terms of supported Java versions), but I converted it to Java 8 for my own amusement and thought to contribute it back.

I toyed with the idea of wiping out HandlerBootstrap / ModuleBootstrap and using more functional constructs to keep all the logic together in HandlerFactory, but I think it detracted from the readability of the example. At the very least, I guess you want this to be a sane starting point for somebody looking to structure their own (maintainable!) app, so oversimplification / over-abstration isn't necessarily a bad thing.

Happy to discuss and refine.