relax SVN archive

Updated the import statements, removing many unused imports.

Added a docstring to the Test_diff_tensor class.

Removed the ability for stand alone execution of the diffusion tensor data structure unit tests.

Stand alone execution is unnecessary as the command:

$ ./unit_test_runner.py data/test_diff_tensor.py

will run the tests.

Three things have been changed. Firstly the system path modifications have been removed. Secondly
the 'if __name__ == "__main__":' block has been deleted. Finally the 'svn:executable' property has
been removed from the repository.

Added the 'generic_fns/' directory to the unit test hierarchy.

Deleted the Pipes class and converted all its methods into module functions.

Updated the data model redesign document to say that point 8 of the preparation is complete.

Renamed 'run' to 'pipe' in the 'generic_fns.runs' module.

The file 'generic_fns/run.py' was renamed to 'generic_fns/pipe.py' and all instances of 'run'
renamed to 'pipe'.

Renamed 'run' to 'pipe' in the 'run' user function class.

The file 'prompt/run.py' was renamed to 'prompt/pipe.py' and all instances of 'run' renamed to
'pipe'. The placing of the user function class into the interpreter namespace was also updated.
The docstrings of all the user functions where modified to use the new terminology.

Updated the 'data_model_redesign' document to state that the redesign of 'self.relax.data' is complete.

Completion of the core of the molecule-residue-spin data structures.

All of the initialisation of the class variables and objects in all six classes have been shifted
into __init__() methods so that new copies of the objects are created when molecules, residues, or
spins are added to the structure.

The __repr__() methods of all classes have been updated and return a proper text representation of
the objects.

The XList class docstrings have been updated.