New MVC GSOC 2014

https://groups.google.com/forum/#!topic/joomla-dev-cms/AH6piuw2IR0

http://gwilson.org/index.php/new-mvc
Because I'm throwing it upstream before the redirect. An exception is there to terminate the process and move to JErrorPage, Or you can for a less serious error return false and throw an error with JApplicationCms->enqueueMessage() etc.