Updated devDependencies
Fix booboo :)
Updated Grunt plugins and functions

Added a bunch of Grunt plugins that are going to assist in finding
missing i18n stuff. Also, the beginning s for JS validation, JavaScript
Lint, JavaScript coding standards which can easily be used for
additional .js files as well.
Standardising the text-domain
Update .pot file
Merge branch 'master' of git://github.com/Yoast/google-analytics-for-wordpress into Prevent-directory-access