relax SVN archive

The relax_disp.cpmg_frq user function can now handle values of None.

The float function is no longer used if the value of None is encountered.

The relax_disp.cpmg_delayT backend can now handle the 'cpmg fixed' experiment type.

Expanded the relax_disp.exp_type user function to include the fixed period CPMG experiments.

The relax_disp.cpmg_delayT user function backend now uses the spectrum ID rather than experiment ID.

Changed the relax_disp.cpmg_frq user function id argument to spectrum_id.

All the relax_disp user functions now operate with the spectrum IDs instead of experiment IDs.

Renamed the relaxation dispersion test suite data directory to 'dispersion'.

Created an icon set for relaxation dispersion.

Fix for the relax_disp.cluster user function.

The 'free spins' category is now not deleted when empty.

Added a warning for the spectrum.read user function if a peak intensity of zero is encountered.

This value can cause singular matrix failures in certain optimisation.

Expanded the write_results() method of the relaxation dispersion auto-analysis.

More Grace graphs are now being produced, and the Rex file creation is now model dependent.