Bug fix for the new 'NS R1rho 3-site' dispersion models - the Y and Z initial magnetisations were switched.
This is for the 'NS R1rho 3-site' and 'NS R1rho 3-site linear' dispersion models.
This follows the tutorial for adding relaxation dispersion models at:
http://wiki.nmr-relax.com/Tutorial_for_adding_relaxation_dispersion_models_to_relax#Debugging.
