PhantomJS alternatives

[hgwood]

• PhantomJS 1.9 does not work on MacOS Sierra (#163)
• PhantomJS 2.1 does not print correct PDFs consistently on all OSes (#164)

What can we do?

• Wait for Chrome 59 (includes Headless Chrome with PDF printing support). Getting Started: https://developers.google.com/web/updates/2017/04/headless-chrome
• Wait for PhantomJS 2.5 (no release date) PhantomJS abandoned
• Wait for Headless Chrome to support PDF printing
• Evaluate PDF generation in Electron
• Evaluate https://github.com/Janpot/electron-pdf
• Evaluate https://github.com/kapouer/node-webkitgtk
• Could we transform the markdown into a PDFKit script?
• Enforce PDF generation to be done in Docker and only support that

[hgwood]

The more I think about it the more the last option makes sense. It would simplify the framework quite a bit. The main drawback is that Docker become a requirement to generate PDFs, but since we now have a CI that does that, I don't see why most users would want to generate PDFs locally. However, we need to make sure the CI is capable of running Docker properly.

[bpetetot]

FYI : Native support of docker available in Circle CI 2.0(beta access only for now)

[hgwood]

@bpetetot I'm not sure it means it will be able to run docker. Rather, that the build can be run inside a docker container. I might be wrong.

[hgwood]

Headless Chrome seems like the go-to solution now.

[hgwood]

Note: moving from Phantom allows us to drop the promise and setimmediate polyfills.

[hgwood]

Closing in favor of #185.