Add ignoring of duplicate 'css' classes

Author: eGavr

lib/utils/utils.js

@@ -51,7 +51,11 @@ function sortCssClasses(attrs) {
     function _sortCssClassesValues(cssClasses) {
         var classList = (cssClasses || '').split(' ');
 
-        return _.filter(classList).sort().join(' ');
+        return _(classList)
+            .filter()
+            .uniq()
+            .sort()
+            .join(' ');
     }
 
     var classIndexes = _getIndexesInArray(attrs, 'class');