Added the 'TP02' model to the specific_analyses.relax_disp.variables module.

This is the Trott and Palmer 2002 R1rho analytic model for 2-site exchange.

This commit follows step 1 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).
Added the 'TP02' model to the relax_disp.select_model user function frontend.

This is the Trott and Palmer 2002 R1rho analytic model for 2-site exchange.

This commit follows step 2 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).
Added the 'TP02' model to relaxation dispersion chapter of the relax user manual.

This is the Trott and Palmer 2002 R1rho analytic model for 2-site exchange.

This commit follows step 2 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).
Added the 'TP02' R1rho' calculating function to the relax library.

This is the Trott and Palmer 2002 R1rho analytic model for 2-site exchange.

This commit follows step 3 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).  The Matlab code from Skrynnikov and
Tollinger has not been converted to Python code yet.  This is to allow the Matlab->Python conversion
to be followed.
Fix for the 'M61 skew' dispersion model indexing in the user manual.
Added the 'NS 2-site expanded' model to the CPMG dispersion sample script.
Added the 'NS 2-site expanded' and 'TP02' models to the script in the manual.

This is in the script section of the dispersion chapter of the user manual.
Converted the lib.dispersion.tp02 module from Matlab code to Python.

The code has also been made fail-safe and repetitive calculations have been shifted outside of the
loop to speed things up.
Fixes for the TP02 model section of the dispersion chapter of the manual.
Created the 'TP02' model target function.

This is the Trott and Palmer 2002 R1rho analytic model for 2-site exchange.

This commit follows step 4 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).
Added support for the 'TP02' model to the relax_disp.select_model user function back end.

This is the Trott and Palmer 2002 R1rho analytic model for 2-site exchange.

This commit follows step 6 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).
The spectrometer frequency information is now checked for the TP02 model.