Implement ES-Lint with Prettier

[brniamut]

I would suggest that ES-Lint is used with a Prettier config so the code-style stays the same if people contribute. Would also suggest to implement this within the Circle CI build so this is done automatically.

https://github.com/prettier/prettier-eslint

If @jeffhuys agrees I can make a pull request.

[jeffhuys]

Sure, sounds good. I'll await your pull request 👍

[jeffhuys]

@brniamut did you ever come around to this? 😋