relax SVN archive

Improved the extracted bond vector print out to show the atom names of the vector.

Brought the Scientific PDB structural object into line with the structural API.

Small print out fix.

Added the missing return_name and return_warnings args to the Scientific PDB bond_vectors() method.

Added the missing return_name and return_warnings args to the structural API bond_vectors() method.

Modified the print out during the extraction of bond vectors.

Fix for the bond_vectors() method - the spin.attached_atom variable is correctly set.

Modified vectors() to use the new data returned by cdp.structure.bond_vectors().

Modified the __find_bonded_atom() and bond_vectors() methods to return more data.

This additional data is the name of the attached atom and any warnings when trying to find the
attached atom.

Added 2 new methods to the internal relax structural object.

These are __find_bonded_atom() and bond_vectors().