Add examples of alternative scoring metrics

[buske]

Right now, scoring is implicitly provided by elasticsearch. It would be helpful to demonstrate several simple scoring metrics, such as the UI score. Ideally, this would be implemented in a way that made the scoring metric easy to change or configure.

[Relequestual]

This sounds good to me! Can I suggest that where libraries are used to make calculations, if the documentation is not suffeciant to explain, then include some suplementary documentation?

[buske]

Yep, that's a good suggestion. Documentation is nice. :)