Support exporting to JSON Table Schema
For Jupyter based frontends, we would love to see a common tabular format in JSON that we can render (in addition to or in lieu of the current HTML). This would provide us the flexibility to style and format according to data type, as well as have better hooks for theming of tabular data on frontends. Everyone has an opinion, let's give them flexibility to apply it.

It's important to us to support a common JSON format so that for R, Julia, and other languages also can display their DataFrames with similar formatting and styling out of the box.

The best one I've seen so far, with a great amount of discussion and collaboration, is the [JSON Table Schema](http://specs.frictionlessdata.io/json-table-schema/).

Update: In order to include both data + schema, we're using [data resource](http://specs.frictionlessdata.io/data-resource/) which has media type `application/vnd.dataresource+json`.

/cc @captainsafia @ellisonbg @jreback @TomAugspurger 
