relax SVN archive

Changes between analyses are now blocked if the relax execution lock is set.

Layout changes to the value.set user function window.

Improvements to the user function window descriptions.

The process_doc() method has been added to isolate text elements such as tables to allow
differential formatting.

Increased the size of the value.set user function window.

Created the user function base class method add_desc() for creating a custom description element.

Added two more fonts to the gui object.

Fix for the word wrapping of the relax_fit.set_doc documentation string.

Fixes for the relax_data user function docstrings and variable descriptions.

The wizard _add_desc() method is no longer private to allow derived classes to format this text.

Converted the minimisation documentation used in the user functions to the new system.