New MVC GSOC 2014

https://groups.google.com/forum/#!topic/joomla-dev-cms/AH6piuw2IR0

http://gwilson.org/index.php/new-mvc
instead of having $type = null, use $type = 'message' and get rid of the if/else there. Also I'm not sure if you still have a setMessage method or not, but if so, I would forward to that method, so there are not multiple ways to set the message (legacy). This would get rid of the need to check here too.