relax SVN archive

Fix for the calls to generic_fns.align_tensor.get_tensor_index().

The arguments have been changed.

Fix for the structure.get_pos user function.

This has been updated for the atom_loop() structural API method change.

Fix for some unit tests using the atom_loop() structural API method incorrectly.

The model_num_flag arg no longer exists.

Missing import.

The frame order specific API method sim_return_param() now matches the API.

The structural API atom_loop() methods now all have the model_num_flag arg dropped.

Updates to some of the __all__ package lists for the new modules.

Massive speed (20 times) for the structure.vectors user function for the internal structural object.

This is similar to the changes to the structure.load_spins user function whereby the model_loop()
method has been eliminated.

Redesigned the structure.load_spins user function back end for the new atom_loop() method.

Resigned the internal structural object atom_loop() method to be up to 20 times faster.

The base model_loop() method is no longer used at all. It was previously being used in a nested
fashion, making the loop extremely slow when lots of models exist.