relax SVN archive

The spin parameters are now set up last by the relax_disp.select_model user function back end.

Converted all relaxation dispersion parameters to lowercase.

This is so the variable names match the parameter names identically, avoiding problems with some of
the shared methods of the specific analysis API.

Expanded the checking in the Relax_disp.test_exp_fit system test.

The relaxation dispersion parameter errors from Monte Carlo simulations are now stored.

Previously MC simulations could run, but the errors were not being calculated and stored. The
sim_return_param() method was empty. This method is now complete.

In addition the set_error() method has been created for setting the parameter errors. And the
_exp_curve_key_from_index() and _param_index_to_param_info() auxiliary methods added to facilitate
data access.

The Relax_disp.test_exp_fit system test now checks some of the final results.

Modified the Relax_disp.test_exp_fit system test to be faster and not create plots which it cannot.

Activated Monte Carlo simulations for the relaxation dispersion analysis.

This required a bit of work. The key parts weres renaming _block_loop() to the API method
model_loop() as that is exactly what the model_loop() method is supposed to do, converting a bunch
of API common spin-based methods to handle dispersion clustering, and to modify existing methods
from Seb's original branch to handle the base_data_loop() method. The following methods have been
added or modified:

_back_calc(): This method has been modified to handle clustering and the returning of peak intensities
from only one exponential curve.

_exp_curve_index_from_key(): This new method is used to convert exponential curve key into the
corresponding index.

_intensity_key(): This new method is for converting an exponential curve key and relaxation time
into the corresponding intensity key.

create_mc_data(): This method is now functional and handles the data from the base_data_loop() method.

return_error(): This method now handles the data from the base_data_loop() method.

set_selected_sim(): This new method has been modified from the common _set_selected_sim_spin()
method but modified for the model_loop() method.

sim_pack_data(): This method now handles the data from the base_data_loop() method.

sim_return_param(): This new method has been modified from the common _sim_return_param_spin()
method to suit the model_loop().

sim_return_selected(): This new method has been modified from the common
_sim_return_selected_spin() method again to suit the model_loop().

Created a custom base_data_loop() method for the relaxation dispersion analysis.

This defines the base data as the peak intensities of a single exponential curve and yields the spin
container and exponential curve key identifying the individual curves.

Fixes for the dispersion specific _back_calc() method.

This method still has a long way to go before it is of any use.

The relaxation dispersion target function class back_calc variable now matches the values variable.

Instead of being a temporary structure which is overwritten for each spin and each exponential
curve, the structure now matches the dimensions of the values variable and hence is persistent per
function call. This allows external code to access the structure - for example for data back
calculation in the relaxation dispersion specific analysis module.