Explore Use of Vega-Lite as Higher-Level API

[mrblueblue]

Vega-Lite provides a higher level visualization grammar that ties together encodings and data transformations.

It would useful to explore how that grammar maps directly to Vega encodings and the mapd-data-layer transformations.

One possible outcome of this exploration is defining a higher-level parser for vega-lite specifications. This parser would translate vega-lite spec to a vega spec and a data transform spec (to be used by the data layer)

[mrblueblue]

Some exploration of this topic can be found in this repo https://github.com/mrblueblue/mapd-vega-example