Cedar Workflow and API

This is a general issue for thrashing out the Cedar API

There are 2 types of json documents involved with cedar.
### Cedar Templates

These are the source, generic templates, based on the vega spec syntax, with an inputs hash appended.

An example of this would be json describing a generic bar chart - aka bar-chart.json

Stored in portals as `type: chart-template`
### Cedar Chart

This is the combination of a vega spec, with the data source url / embedded data. This is the most commonly consumed form for presentation to the end-user.

An example of this would be dc-bar-chart-of-crimes-by-type-over-the-last-month.json.

Stored in portal as `type: chart`
### API Philosophy
- templates/data can be fetched by cedar, but also may be passed in to avoid additional round-trips.
### API Dependencies
- vega - for the visualization grammar and parsing into d3 based charts
- d3 because vega depends on it and also used to fetch data
# Public API

moved to http://esridc.github.io/cedar/api-reference/