Get rid of Jade, use something different

Possible improvement: we don't really like Jade with its significant whitespace for HTML. There are [other view engines](http://wildermuth.com/2014/3/24/Choose_Your_Own_Adventure_with_Node_js_View_Engines) ([myriads of them](https://www.quora.com/What-is-the-best-Node-js-template-engine)) as well, we might swap it one day.
