relax SVN archive

Docstring fix in the relaxation curve-fitting linear_constraints() function.

The pivot point x, y and z coordinates are now registered as parameters of the frame order analysis.

These are stored as the parameters pivot_x, pivot_y and pivot_z.

Docstring update for the relaxation dispersion linear_constraints() function.

Fixes for the frame_order.pivot user function - the model parameters were not being updated.

The update_model() function is now called to make sure that the pivot point is either added or
removed from the list of model parameters.

Changed the title for the value user function class.

Changed the title in the value.write user function documentation.

Updated the value.set user function documentation for the frame order theory.

The value.set title has been changed to not be spin specific and a table of the frame order
parameters has been added. The spin ID documentation has also been rewritten.

Improvements for the value.read user function documentation.

The N-state model parameter table has been removed as these parameters are not spin specific and
cannot be read from a file. And the title has been modified.

Improvements for the value.display user function documentation.

The N-state model parameter table has been removed as these parameters are not spin specific and
cannot be used. And the title has been modified.

Updated the value.copy user function documentation for the frame order theory.

The value.copy title has been changed to not be spin specific and a table of the frame order
parameters has been added.