Add support for datastore data to choropleth maps.

[bryanhirsch]

DKAN datastore does pagination, which breaks choropleth maps. Choropleth works around this by only using data from static file uploads right now.

[teosibileau]

@acouch @bryanhirsch i think this issue could use some external help (non-drupal) to make it work because its going to be an issue with every API that returns paginated json.

One way to go at it will be to have the recline view in it's own repo (like https://github.com/okfn/recline.view.flotr2) and add it to choropleth as a library. Maybe ping the okfn guys or some js viz group after that?

I could help with the doc and gh-page.