MasonX::WebApp works with Mason to let you do processing before Mason is ever
invoked. There are a number of things that one might want to do:

* Argument munging

	You might want to make sure all incoming arguments are UTF-8 encoded.
	Or you might want to create some objects which Mason will see as
	incoming arguments. For example, a "user_id" parameter could be turned
	into a user object.

* Handle requests without Mason

	If you're not generating output for the browser other than a redirect,
	then there's no reason to use Mason. You can use a MasonX::WebApp
	subclass to handle all form submissions, for example.

	This has the added benefit of making it easier to preload this code
	once during server startup.

* And others ...