bump grunt-contrib-cssmin to ~0.11.0

Gruntfile.js

@@ -114,7 +114,6 @@ module.exports = function (grunt) {
 
     cssmin: {
       options: {
-        banner: '', // set to empty; see bellow
         keepSpecialComments: '*' // set to '*' because we already add the banner in sass
       },
       ratchet: {

package.json

@@ -31,7 +31,7 @@
     "grunt-contrib-concat": "~0.5.0",
     "grunt-contrib-copy": "~0.7.0",
     "grunt-contrib-csslint": "~0.3.1",
-    "grunt-contrib-cssmin": "~0.10.0",
+    "grunt-contrib-cssmin": "~0.11.0",
     "grunt-contrib-jshint": "~0.10.0",
     "grunt-contrib-sass": "~0.8.1",
     "grunt-contrib-uglify": "~0.6.0",