relax SVN archive

The fix user function now uses the diffusion tensor set_fixed() method.

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.