Add a blink comparator and pixel difference to image diffs

Tom

2014-11-17 b6f47539cd1a1dafe05ffd6fdc40bce4547c479d

 src/main/java/com/gitblit/wicket/ExternalImage.java

@@ -27,6 +27,7 @@
      super(id, new Model<String>(url));

   }



   @Override

   protected void onComponentTag(ComponentTag tag) {

      super.onComponentTag(tag);

      checkComponentTag(tag, "img");