relax SVN archive

Fix for a fatal bug in the rarely used structure.add_atom user function.

The position argument in the user function definitions was incorrectly defined causing the user
function to be non-functional.

Fixed a docstring talking about RDC data in the dispersion analysis.

Implemented the relax_disp.r2eff_read_spin user function.

This allows R2eff/R1rho files for each spin to be read.

Fixes for the Relax_disp.test_r2eff_read_spin system test.

Fixed a typo in the user function name in the Relax_disp.test_r2eff_read_spin system test.

Fix for a duplicated line typo in the Relax_disp.test_hansen_cpmgfit_input system test.

Fixes for all of the Relax_disp system tests which use Flemming Hansen's CPMG data.

These are needed due to the improved error estimates in the data files.

Fixes for the Relax_disp.test_hansen_cpmg_data_auto_analysis* system tests.

The Relax_disp.test_hansen_cpmg_data_auto_analysis system test needed updating due to the more
accurate R2eff errors. The Relax_disp.test_hansen_cpmg_data_auto_analysis_r2eff system test also
needed this change. It also no longer has a spin system for residue 4.

Fix for return_index_from_disp_point() for when R2eff/R1rho data is loaded rather than intensities.

This specific_analyses.relax_disp.disp_data.return_index_from_disp_point() function was always
subtracting 1 from the dispersion point index to take the reference spectrum into account. This
however fails if R2eff/R1rho data is loaded instead.

Improved the R2eff errors for Flemming Hansen's CPMG data.

The errors are now calculated using the data from all spins rather than a truncated subset. The
errors will therefore be much more accurate.