Simplified the dispersion experiment type classes.

The supported types will now be 'CPMG' and 'R1rho', as the fixed time verses full exponential curve
can be automatically determined by relax from what the user inputs.

The EXP_TYPE_* dispersion variables have all changed and many have now been lost.  To support the
changes, the new specific_analyses.relax_disp.disp_data.loop_spectrum_ids() function has been
created.  This is a loop over all spectrum IDs whereby the experiment type, magnetic field strength,
dispersion point, or relaxation time can be specified to isolate ID subsets.

Many of the specific_analyses.relax_disp.checks.check_*() has also been modified as their logic no
longer works.  The auxiliary get_times() function has been added to create a per-experiment
dictionary of relaxation times so that the checks can be independent of the other dispersion
modules.
Updated much of the dispersion test data for the changes of r20894.

The experiment type has been changed in all the scripts and the relax save files updated.
Fixed missing space typo.

Progress sr #3071: https://gna.org/support/index.php?3071 - Implementation of Tollinger/Kay dispersion model (2001)
Following the guide at: http://wiki.nmr-relax.com/Tutorial_for_adding_relaxation_dispersion_models_to_relax

Troels E. Linnet provided this patch. Commit by: tlinnet _aaattt_ gmail_dot_com

Signed-off-by: Edward d'Auvergne <edward@nmr-relax.com>
Fixed expydoc formatting.

Progress sr #3071: https://gna.org/support/index.php?3071 - Implementation of Tollinger/Kay dispersion model (2001)
Following the guide at: http://wiki.nmr-relax.com/Tutorial_for_adding_relaxation_dispersion_models_to_relax

Troels E. Linnet provided this patch. Commit by: tlinnet _aaattt_ gmail_dot_com

Signed-off-by: Edward d'Auvergne <edward@nmr-relax.com>