Jslint added

Jslint added to clean up code.

[Nodelint](https://www.npmjs.org/package/nodelint) can be used to run Jslint from the command line, additional Jslint options can be added to `jslint_options.js` Then you can run it from the command line.

Example `nodelint index.js --config jslint_options.js`