Antz_IntelliForm: Save submitted forms to prevent reposting warnings

This class can be used to prevent form reposting warnings by saving submitted form data.

It saves the values of forms submitted using the POST method to session variables for a given length of time.

Then it makes the browser redirect to the same page forcing a new request, this time using the GET method.

The form values previously submitted using the POST method are restored from the session variables.

This way, when the user returns to this page using the browser reloading the page or using the back button the browser willing display warnings saying "Are you sure you want to resubmit the form?"

The class can also generate hidden inputs with random values also stored in session variables to prevent Cross-site request forgery exploit attempts.