relax SVN archive

Converted the assemble_param_vector() model-free method to the new relax design.

Converted the assemble_param_names() model-free method to the new relax design.

Renamed the module to avoid a name clash.

Shifted all of the model-free optimisation related methods into a separate module.

Bug fix for the system test of AIC model selection between two diffusion tensors.

The diffusion tensor was not been properly set up.

Converted the grid_search() model-free method to the new relax design.

The grid_search_setup() method has been merged into this method.

Cleaned up the code of the overfit_deselect() model-free method.

Converted the overfit_deselect() model-free method to the new relax design.

Converted the select_model() model-free method to the new relax design.

Fixes for all the unit tests of the generic_fns.value.partition_params() function.