Gulp: added 'cleanup' task that erases all gulp-generated files.

This runs automatically when using --production

package.json

@@ -13,6 +13,7 @@
 		"gulp-chmod": "~1.3.0",
 		"gulp-concat": "~2.6.0",
 		"gulp-if": "^2.0.1",
+		"gulp-git": "~2.4.2",
 		"gulp-jade": "~1.1.0",
 		"gulp-livereload": "~3.8.1",
 		"gulp-plumber": "~1.1.0",