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).
Authored by: bugman 2013-07-31
Parent: [r20484]
Child: [r20486]
