The spectra list GUI element in the dispersion auto-analysis now shows all columns.
Removed the temporary FIXMEs from the relax_disp.exp_type user function backend.

This is needed to enable the mixed experiment type code to be developed further, but means that the
relax_disp branch will be broken for a while!
The specific_analyses.relax_disp.disp_data.loop_point() function now requires the exp_type argument.

The exp_type can no longer be determined within the loop_point() function.  Therefore it must be
specified using a function argument.  The rest of the module has been updated for this change.