#1158 Single-page app routing

* Controllers now export a function that extends current app, rather than a new one (SPA router needs instances of `app.get()` to be declared in current instance of app).
* Added static _Hello world!_ page in `/public/angular`
* Exposed `/public/angular` as a static page in `/`
* Added single-page app routing for `/`
* Make sure you run `npm install`