Consider migrating tests to Nightmare or other headless browser

[imaustink]

Zombie isn't terrible but it's built on top of jsdom and thus has a limited implementation of the DOM. For certain tests, we have to make exceptions for Zombie and bypass functionality. In my opinion this is ugly and wrong. Not to mention the fact that you can't inspect code running in the Zombie browser, making debugging a real pain.

I'm not certain Nightmare can fix all of this, but I am confident it will fix some of our problems. I think it would be wise to investigate further.

[leoj3n]

Specifically, we should try using it with a test that was failing with a version of steal before that fix for zombie was made, and also see if it supports dataset unlike zombie.

[leoj3n]

https://developers.google.com/web/updates/2017/04/headless-chrome