Remove lodash and grunt.util._

* I replaced [`grunt.util._.contains`](http://lodash.com/docs#contains) with [`Array#indexOf()`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf), because [grunt.util._](http://gruntjs.com/api/grunt.util#grunt.util._) is [deprecated](http://gruntjs.com/blog/2013-11-21-grunt-0.4.2-released).
* I removed [`lodash`](https://npmjs.org/package/lodash) module from dependencies, because [`_.map`](http://lodash.com/docs#map) is substitutable with native [`Array#forEach()`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach) in this case.