*This plugin was designed to work with Grunt 0.4.x. If you're still using grunt v0.3.x it's strongly recommended that [you upgrade](http://gruntjs.com/upgrading-from-0.3-to-0.4), but in case you can't please use [v0.3.2](https://github.com/gruntjs/grunt-contrib-clean/tree/grunt-0.3-stable).*