Added checking of a submission's status into the functions that create the Web forms and process the submitted data. If the submission's status is set to 'finished', WebSubmit will not continue to process the submission. Instead, it will display a message saying that the submission has been completed, providing a link to the submission homepage of the doctype that was last submitted. This corrects a bug that was encoutered when users used their browser's back button to return the Web Form to start a new submission. Such an action could lead to data loss problems and unstable behaviour during the submission. This has now been prevented.