Removed some debugging printouts accidentally committed in the last commit (r21930).
Removed a printout from the Relax_disp.test_r1rho_kjaergaard GUI test as this is fatal for Python 3.
Python 3 fixes for the relax_disp.r2eff_read_spin user function.

The check for the dispersion point column now only runs if that argument is set.  In addition, the
offset column is now also being checked.