Links to D3 V4 module list which closes #39

[migbar]

[ivanvanderbyl]

It'd be better if you actually included the list in the readme, instead of linking to an external gist.

[voodoologic]

before I had read through this, I was going to open another issue. I couldn't find where the event module was.
This is my first time using d3. I had some issues trying to invoke the imported libraries inside of the debugger console (you can't without assigning it to a variable first). Despite this I REALLY have been appreciating the work that has been going into this project. It has revealed the power of web-components and d3. kudos.

[ivorscott]

This addon allows us to specify the d3 version. So a module list may change depending on the version. We are better off just curling the raw package.json from the d3 version we want. Then we simply check the d3 dependencies.

curl https://raw.githubusercontent.com/d3/d3/v5.1.0/package.json