Cleanup codebase and fix formatting

[typerandom]

Important

This branch was based off of #29. Because that contained quite a bit of refactoring already. So that one needs to be reviewed/merged before this one is.

What this include

• Formatting validation using ESLint. Same that we have in our other Node.js projects.
• Seperation of prototypes and helper functions in index.js into separate logical files.

How to verify

Look through the changes in the codebase and run the tests. Run $ npm run lint to assert that the formatting passes the lint requirements.

Fixes #21

[coveralls]

Coverage decreased (-68.2%) to 31.839% when pulling 1563ec2 on fix-formatting into 9e177c3 on master.

[typerandom]

For some reason coverage has dropped. This refactor should not have affected coverage in any major way. So it's probably because of the new file separation that is causing some tests to not report correctly. I'm going to look into this.

[coveralls]

Coverage remained the same at 100.0% when pulling 1c76f84 on fix-formatting into 9e177c3 on master.

[coveralls]

Coverage remained the same at 100.0% when pulling d46d1f9 on fix-formatting into 9e177c3 on master.