create node project

[ijlyttle]

maybe something inside of data-raw/

eventually, something needs to be put into inst/

there will be three projects, each of which will produce a script:

• to-vega-vl5
• to-vega-vl4
• to-svg-vg5

[ijlyttle]

goals:

• get something working to compile Vega-Lite -> Vega, within node
• get it rolled up and transpiled
• install the script in inst/, get it tested from R using V8