Refactor/write of Nancy.Hal

So, it does have breaking changes on the configuration API...

I'm planning on using this in a API I'm working on, and it looked like the project could do with a bit of love. I beefed up the tests, and made the config a bit more "fluent".
The JSON side is fine, the XML serialisation is coming.

Just wondered what your thoughts were, and how likely you'll pull?