Changes

* [http://www.nmr-relax.com/api/3.1/target_functionsspecific_analyses.relax_disp.Dispersionoptimisation-classmodule.html#func_NOREX back_calc_r2eff API documentation(for exponential curves)],* [http://www.nmr-relax.com/api/3.1/specific_analyseslib.relax_dispdispersion.optimisationtwo_point-module.html#back_calc_r2eff relaxation dispersion page of the relax website] calc_two_point_r2eff API documentation (for exponential curvesthe 2-point fit),].* [http://www.nmr-relax.com/apianalyses/3.1/lib.dispersion.two_point-modulerelaxation_dispersion.html#calc_two_point_r2eff R2eff relaxation dispersion page of the relax website] (for the 2-point fit).