add authors support, and tests

* Syncs npm's `'author'` property and `'contributors'` array to Bower's `'authors'` array.
* Because this adds enough complexity, it warranted adding tests with mocha + chai via `npm test`.
* Also added jshint as dev dependency, and `npm run-script jshint`.

Do you intend to use Grunt for build/test on this project, or no?