Rewrite all requests to the public folder

Having seen the continued discussions going on on #79 - here is a functional PR with the minimal changes originally outlined.

This means that users can choose between:

 * Drop in install. http://localhost/php-mvc **just works**
 * Drop in install. http://localhost/ **just works** if in the document
 * root **just works**
 * Create a vhost pointing at the public folder **just works**

fixes #79