Add editorconfig and linting

[frozegnome]

With more people looking to contribute, it would be a good idea to get an editorconfig and linting style in place (standardjs, airbnb, etc.)

[ConnorBryan]

This might be a good idea -- not a fan of either AirBnB or Standard, though.

[frozegnome]

What do you not like specifically? We can see what works well based on omitting certain rules etc.