relax SVN archive

Added a dummy build_widget() method so that the derived classes need not provide it.

Removed a pile of unused code in the references window.

Most was to do with backwards and forwards navigation.

The about window base class can now render given HTML text to the DC.

Created a script for debugging the model-free auto-analysis about window.

Created a directory for scripts which launch elements of the GUI independently of the GUI.

This is for debugging purposes, and an initial script has been added for the references window.

The destroying of the window on clicking is now optional.

The about window style is now a class variable, so the model-free window now has a border.

Explicit keyword arguments are now used in the about window classes.

Decreased the width of the text slightly in the model-free about window.

The setting of the about window virtual size has been shifted to the virtual_size() method.