Replaced API function in specific_analysis.relax_disp.api to calculate and return values for parameter theta() when this is requested.
Regarding sr #3124, (https://gna.org/support/index.php?3124) - Grace graphs production for R1rho analysis with R2_eff as function of Omega_eff.
Implemented according to http://www.mail-archive.com/relax-devel@.../msg05082.html.
Authored by: tlinnet 2014-03-12
Parent: [r22453]
Child: [r22455]
