http://jsonlines.org/ support

[bkamins]

I encounter http://jsonlines.org/ more and more often recently. Maybe we can also add a function to read in the data in this format?

[quinnj]

I've put up a PR to support JSON-lines reading in JSON3.jl: quinnj/JSON3.jl#99. Once it supports it, we can pass through the option in jsontable as well.