added grunt and grunt-ngdocs as deps and setup documentation site

helpful links for using ngdocs
https://github.com/angular/angular.js/wiki/Writing-AngularJS-Documentation
https://www.npmjs.org/package/grunt-ngdocs
https://github.com/angular/dgeni-packages/blob/master/NOTES.md
https://github.com/m7r/grunt-ngdocs