last eslint fixes

[brendankenny]

should settle everything outstanding in #4

• enforces line length of 80
• enforces single quotes (allows backticks as long as something is being interpolated (see Allow enforcing single/double-quotes without preventing use of template literals eslint/eslint#5234 for that whole debate))
• settles on resolve/reject (instead of res/rej) for Promise executor signature since that's winning the current popularity contest in the repo