This required a number of modifications:
- The user function object wizard creation has been shifted into the create_wizard() method.
- The status.gui_uf_force_sync flag has been introduced to force synchronous operation of the
GUI user functions.
- The wx_wizard_run keyword arg has been added to the user function object to prevent the
automatic running of the wizard.
- The GUI test tearDown() base method no longer destroys the GUI or wizards, as they are needed
in subsequent tests.
