Replicate examples from Vega-Lite site

[mhkeller]

Thanks for this library. It would be great as a quick reference to have the examples in the Vega-Lite gallery shown using this API.

It's a big lift, though, so one way to make it easy for folks to contribute would be to create a project scaffold with the output specs of each of those existing vega-lite examples. That way, people could fill in the JS api and the repo could run a test to validate the output against the spec. I'd be happy to help set that up if you're interested.