relax SVN archive

Added support for model nesting in the relaxation dispersion auto-analysis.

This involves copying the parameters from the simpler nested model rather than performing a full
grid search. This is currently used to handle all models with R20A and R20B parameters where a
simpler model with the single R20 parameter is optimised first.

Small speed up for the lib.dispersion.cr72 module for the R20A != R20B case.

Replicated calculations have been minimised.

Documentation fix for the lib.dispersion.cr72 module.

Better printouts of the R20A and R20B parameters at the end of minimisation.

Fix for the dispersion specific loop_parameters() method for the R20A and R20B parameters.

The frequency index is now correctly returned for these and the R20 parameter.

Expanded the CR72 model to handle both the R20A and R20B parameters.

The 'CR72 red' model now functions as the old CR72 model where R20A = R20B = R20. All parts of the
code have been modified. The lib.dispersion.cr72.r2eff_CR72() function has been expanded to support
the full Carver and Richards 1972 equations, dropping back to the simplified form if R20A = R20B.

Small fix for the dispersion chapter of the user manual.

LaTeX improvements for the 'NS 2-site star red model' section of the dispersion chapter of the manual.

Added the 'CR72 red' model to the relax user manual.

This is the Carver and Richards 1972 analytic model with the simplification R20A = R20B. The
current 'CR72' makes the same assumption, but that model will be expanded to support R20A and R20B
later.

This commit follows step 2 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).

Added support for the 'CR72 red' model to the relax_disp.select_model user function back end.

This is the Carver and Richards 1972 analytic model with the simplification R20A = R20B. The
current 'CR72' makes the same assumption, but that model will be expanded to support R20A and R20B
later.

This commit follows step 6 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).