Added proper asset exclusion for production

Assets currently are parsed by the controller, when they should simply be ignored and sent to a webserver 404 when in a production environment.

A 404 ErrorDocument is added so that bad assets are sent to a cakePHP 404 page or could be modified to load a 'static' page

This removes bad assets from the Controller logic and prevents overloading the server when improper asset requests are made

Added htaccess rules for production
Merge pull request #617 from TeckniX/patch-1

Added proper asset exclusion for production