Removed unused and JSHint dependency

This removes the unused and incorrect dependency on JSHint; and instead moves it to a `devDependency`.

This supersedes #5 

After this is merged we should run:

```shell
npm version minor
npm publish
```

And then update its dependents to point to the new version.
I think the most correct thing to do is to make this a `peerDependency`, but since this package so probably go away, we'll just remove the runtime dependency altogether for now.