relax SVN archive

Added unit tests for the methods of the classes of the module 'data.mol_res_spin'.

Added unit tests for the functions of the module 'generic_fns.pipes'.

Updated the docstring of 'generic_fns.pipes.create' to be in Epydoc format.

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'.