njwt Cleanup codebase and fix formatting

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

Oct 03 '16 15:10 typerandom

Coverage decreased (-68.2%) to 31.839% when pulling 1563ec2e19069bc57bf8a671f498b0b952901cff on fix-formatting into 9e177c3c796b53e9696a696aa012d58ece01f08c on master.

Oct 03 '16 15:10 coveralls

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.

Oct 03 '16 16:10 typerandom

Coverage remained the same at 100.0% when pulling 1c76f84b6dde764e4bd387504b502b3c2615b3aa on fix-formatting into 9e177c3c796b53e9696a696aa012d58ece01f08c on master.

Oct 05 '16 15:10 coveralls

Coverage remained the same at 100.0% when pulling d46d1f96c9276e90468de75d098cd92d2d93dca1 on fix-formatting into 9e177c3c796b53e9696a696aa012d58ece01f08c on master.

Oct 07 '16 13:10 coveralls