relax SVN archive

Converted all of the user function GUI pages to use the new create_wizard() base method.

This significantly simplifies the code. The functions also no longer expect a wx event.

The deselect user function GUI pages no longer expect the uf page to be returned.

Added the return_page arg to create_wizard() so that the user function page can be selectively returned.

Complete redesign of the user function menu system.

This is now more flexible and should be more compatible with window ordering under MS Windows.

Simplified the deselect user functions using the new GUI uf design.

The create_wizard() method now returns the user function page.

This will be needed as sometimes the fields have to be changed.

Redesigned how the user function wizards are created.

The create_wizard() UF_base class method has been added to perform most of the work and to simplify
the specific user function code. The __init__() method has also been reintroduced, but this time it
takes the 'parent' arg, which is the parent wx.Window, via the User_functions package class.

Added the parent arg to the Wiz_window class.

This will allow the parent of the wizard to be specified, hopefully fixing the MS Windows window
ordering issues.

Removed the now useless UF_base.__init__() method.

The User_functions class no longer takes any arguments.