Upgraded grunt-contrib-jshint to version 0.4.
Upgraded grunt-contrib-jshint to version 0.5.
Upgraded grunt-contrib-nodeunit to version 0.2.
Upgraded grunt-contrib-jshint to version 0.6.
Removed es5 option from JSHint config file.

This option is now redundant because JSHint assumes ES5 by default.
Added Gemnasium dependencies badge to the readme.
Added NPM module version badge to project readme.