relax SVN archive

The setting of list values for the DiffTensorSimList object now works correctly.

The private _set() method now works correctly by calling the base class method, and the normal
setting of diffusion tensor simulation values produces a RelaxError.

Fix for the diffusion tensor __deepcopy__() replacement method for the new design.

The model-free specific analysis _disassemble_param_vector() method now uses the new diffusion tensor design.

Modified the setUp() method for the diffusion tensor system tests to use the new design.

Redesigned how diffusion tensor simulation structures are handled.

The design is now much cleaner and works with all Python versions.

Removed all the unused imports from specific_fns.model_free.main.

A number of private diffusion tensor objects and methods have switched to the single leading '_' format.

Improvements to the diffusion tensor set() method.

The parameters, errors and simulations are now properly differentiated and stored.

Converted the old diffusion tensor __setattr__() method into the set() method.

This is the only way in which diffusion tensor parameters, errors and simulations can be set.

Renamed the diffusion tensor data structure type() method to set_type().

This is because the type is stored as the 'type' object, clashing with the method name.