fix https://github.com/ajaxorg/ace/issues#issue/80

lib/ace/layer/gutter.js

@@ -73,7 +73,7 @@ var Gutter = function(parentEl) {
     this.setAnnotations = function(annotations) {
         // iterate over sparse array
         this.$annotations = [];        
-        for (var row in annotations) {
+        for (var row in annotations) if (annotations.hasOwnProperty(row)) {
             var rowAnnotations = annotations[row];
             if (!rowAnnotations)
                 continue;