Created the specific_analyses.relax_disp.data.is_r1_optimsed() function.
This follows from an idea for handling R1 optimisation in the tread at
http://thread.gmane.org/gmane.science.nmr.relax.scm/22850/focus=6736.
This relaxation dispersion function can be used anywhere that requires the knowledge that R1 values
should be fitted during optimisation or if loaded values should be used.
