complete haddock comments with examples for `Citeproc` and `Citeproc.Types`

[andrewufrank]

Congratulation for the new citeproc package!

I tried to read the documentation to understand how to use it in building webpages from markdown files. I am not a pandoc or bibtex specialist (my interest is spatial ontologies) and had difficulties to see what the functions do, because the terms you use are (for me) polysemous and it is difficult to grasp what you intend. The solution is simple: add an example and things become clear at once (works mostly...).

Practically: could you add a simple example in the haddock comments for the top classes, as you did for data Citation a in http://hackage.haskell.org/package/citeproc-0.3.0.9/docs/Citeproc-Types.html#t:Citation. I think this is easy to do and would help a lot to clarify how to use the new modules.

Thank you for inventing pandoc and keeping it!