relax SVN archive

Fix for the logic in the recycling of old user function wizards.

Fix for the system test base script running method script_exec().

This now calls the interpreter, rather than itself in a circular loop!!!

Removed the useless GUI interpreter flush() call in the GUI tests base _execute_uf() call.

This is not needed as the GUI user function calls are synchronous. This cuts the GUI test
running time down by about 1/4!

Fix in the GUI uf page SetValue() method for the sequence.display user function.

The uf has the 'sep' arg, but this is not part of the free file format set of args! The SetValue()
method is now checking if the free file format is active for the page, before assuming an arg is
part of that set.

The wizards for the individual user function pages are now recycled.

This should speed up the GUI (and the GUI tests massively). Closing the wizard calls the Close()
rather than Destroy() method, so the wizards are still in memory. A new call to an old GUI uf
object will simply call SetValue() for all keyword arg GUI elements, hence reset the element.

The Wizard GUI object has been modified to only add the buttons if they do not currently exist.
Without this, a new set of buttons is added each time the user function wizard appears.

The GUI base class now has access to math.pi.

This is necessary as the system test scripts are run in this namespace rather than the interpreter
namespace which has pi defined.

The Combo_list GUI input element can now handle values typed out by the user.

This affects both the GetValue() and SetValue() methods.

The value.set user function 'param' arg can now be manually set by the user rather than selected.

A number of N-state model parameters require this.

Better handling of empty data in the Sequence.GetValue() method.

The non-supplied user function args in the GUI tests are now set to the default.

This is for the _execute_uf() base method, and is essential for the free file format where the
column args must, in many cases, be set to None.