relax SVN archive

Renamed the diffusion tensor fixed() method to set_fixed() to avoid clashing with the 'fixed' object.

Fix for the model-free specific analysis duplicate_data() method for the new design.

The diffusion tensor __mod_attr__ object is now called _mod_attr.

Fix for the diffusion tensor to_xml() method for the new design.

For some reason the methods of the Element class are no longer blacklisted.

Converted the diffusion tensor data structure from_xml() method to the new tensor design.

Fix for the Diffusion_tensor.test_copy system test - the simulation parameters are now read-only.

Instead, the diffusion tensor set() method needs to be called.

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.