relax SVN archive

The diffusion tensor copying system test is now more comprehensive.

The test_create_diff_tensor_pdb_ellipsoid() system test has been made more vigorous.

The copy operations are now better tested.

Bug fix for the copying of diffusion tensors data structures.

The DiffTensorSimList objects in DiffTensorData were not being properly copied! This has been fixed
by writing class specific __deepcopy__() methods for both classes. The Element class has also been
subclassed from 'object'.

Fix for the test_copy() system test.

The wrong indices were being checked.

Extended the test_copy() system test to properly check if a copy is made, rather than link.

Bug fix for the __update_sim_append() method.

Now the diffusion tensor simulation structure appending works if the structure doesn't already exist.

The spherical diffusion tensor system tests are now properly set up.

Bug fix for the diffusion tensor MC sim data structures.

All structures are now properly updated when a value for a single simulation changes.

The diffusion tensor MC sim data is now properly set up.

The ellipsoid diff tensor PDB file is now being checked, line for line.