Now clicking cancel button returns user to previous page. Fixes issue 569.
If you don't want that behaviour you can define cancel_redirect and user will be redirected to given url on "Cancel" button click instead of redirecting to previous page.
Patch by: Daniel Hans & Pawel Solyga
Benjamin Niemann <pink at odahoda dot de>: Main developer of Python target.
Clinton Roy <clinton.roy at gmail dot com>: AST templates and runtime.