relax SVN archive

The script GUI user function is now operational again.

The interpreter object is now imported and the synchronous apply() rather asynchonous queue() method
is now used. This allows the execution lock to be released by the script at the end.

The script user function GUI element now uses wx.GetApp() to access to the relax controller window.

The GUI Main instance is now stored in the wx.App as self.gui.

This will allow access to the GUI class via wx.GetApp() calls, avoiding the need to pass the
instance around.

Fix for the script user function GUI element for opening the file dialog.

Removed some now unused class variables.

More indentation fixes (introduced at r14608).

Fix for an indentation problem introduced at r14608.

Fixes for the relax controller and pipe editor and results viewer windows under MS Windows.

These windows were all dark grey, the default frame colour under MS Windows. Now all elements are
packed into a wx.Panel which sits inside the wx.Frame.

Added checks for a current data pipe to a number of GUI user function pages.

This prevents relax errors when trying to launch the user functions but when no data pipes exist.

The screen is no longer cleared prior to relax execution on MS Windows.

This prevents the Windows PowerShell history from being wiped out.