Renamed find_intensity_keys() function to find_intensity_key() to reflect only returning one spectrum id.
Regarding bug #21344, (https://gna.org/bugs/index.php?21344) - Handling of in sparse acquired R1rho dataset with missing combinations of time and spin-lock field strengths.
Implemented as suggested in: http://thread.gmane.org/gmane.science.nmr.relax.devel/5109
