relax SVN archive

Removed the heteronuc arg test of the structure.vectors() user function.

This argument is no longer present.

Fixed all the unit tests of generic_fns.selection.generate_spin_id_data_array().

The function was recently renamed from generate_spin_id() to generate_spin_id_data_array().

Wrote the test_Selection_full_spin_id() for testing the string identifier '#Ap4Aase:2&:Glu@...&@NH'.

Added the start of the regular expression description in the id_string_doc string.

Fix for the atom_id string.

Started to write the new structural API method attached_atom().

Started to recode the vectors() function.

The structural API atom_loop() approach is completely wrong, so the spin_loop() will be used
instead.

The full spin info is now returned from return_spin() and the modified spins written to stdout.

Added the full_info flag arg to return_spin() to allow more info to be returned when desired.

This flag will cause the molecule name, residue number and residue name to be returned in addition
to the spin container.

Deleted the xh_vector() method from the API base class and Scientific Python PDB data object.