relax SVN archive

Boolean argument types are now supported by the auto-generated GUI user functions.

The Selector_bool object and element_bool() wizard page method have been written for this.

The can_be_none user function argument argument is now used.

This is needed for proper argument checking in the auto-generated user functions.

The wizard page GetValue() method now returns None if the corresponding key is missing.

This is needed for the directory arguments as these are not shown in the GUI.

Improvements to the element_file_sel() wizard page method.

Created the special Selector_file wizard element object.

This is modelled on the file_selector() wizard page method.

Created the element_dir_sel() and element_file_sel() wizard page methods.

This will require the selector objects to be written!

The auto-generated GUI user functions objects now support the special UI types.

This includes the file and dir selection dialogs, and skipping the dir args.

The arg_type argument for the auto-generated user functions is now accepted.

This will be used to allow special UI elements to be used for the argument, for example a file
selection dialog.

Integers and string list of lists are now accepted by the auto-generated GUI user functions.

Expanded the wizard page element_int() method to accept all the args of element_string().

All these args will be handled properly by the Integer class as this derives from Base_value.