relax SVN archive

Modified the 'generic_fns.residue.copy()' function to work with the modified 'return_molecule()' fn.

Five unit test were failing due to the previous commit. This was because of a problem in
'generic_fns.residue.copy()' that wasn't previously detected.

Added the 'return_single_molecule_info()' function and fixed the 'return_molecule()' function.

The 'return_molecule()' function was returning a molecule container when no molecule selection was
given. Now None is returned.

Added a unit test for the copying of the molecule data between different data pipes.

Renamed the user function 'molecule.add()' to 'molecule.create()' in the redesign doc.

Removed the useless molecule user functions remaining from the copy from 'prompt/sequence.py'.

Created the molecule.create() user function.

The user function and the function generic_fns.molecule.create() have been written. Two unit tests
for the function have been created.

Updated the module names in '__init__.py'.

Replace the contents of 'generic_fns/molecule.py' with those of 'generic_fns/residue.py'.

The file originated from 'generic_fns/residue.py' but was unmodified and out of date.

Added the setUp and tearDown functions for the generic_fns.molecule function unit tests.

Created the module docstring.