Updating Grunt devDependencies.

* Implemented `grunt-contrib-jshint` to Grunt process.
* Updated the following:
 * Grunt v0.4.2
 +    "grunt-contrib-concat": "0.3.0"
 +    "grunt-contrib-copy": "0.5.0"
 +    "grunt-contrib-imagemin": "0.4.0"
 +    "grunt-contrib-jshint": "0.8.0"
 +    "grunt-contrib-less": "0.8.3"
 +    "grunt-contrib-uglify": "0.2.7"
 +    "grunt-contrib-watch": "0.5.3"
 +    "grunt-svgmin": "0.3.0"
 +    "grunt-jekyll": "0.4.1"
 +    "grunt-favicons": "0.6.0"