relax SVN archive

Corrected a typo introduced in r6815.

Fix for the bond_vectors() method, some variables needed to be initialised to None.

Fix for the bond_vectors() method, some variables needed to be initialised to None.

Fix for the check of pre-existing bond vectors.

Fix for the vectors() function. The spin name or number check now correctly works.

Fixed the calls to the structure.vectors() user function.

Fix for the extraction of bond vectors.

When all vectors are asked for, now all vectors are placed into the spin container.

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.