relax SVN archive

Some changes towards the new design.

The script doesn't work yet and will be introduced into the test suite for further debugging.

The internal PDB object atom_loop() method now can return the average atom properties, if asked.

The internal PDB object atom_loop() method now recognises the ave arg, but does nothing when True.

Added the str_id arg to the Scientific PDB object atom_loop() method.

Added the ave arg to all atom_loop() methods to allow just the average properties to be returned.

Docstring modification for the atom_loop() internal PDB object method.

Added the str_id arg to the atom_loop() structural API method.

Added the ability to select the structure to load the spins from in the load_spins() main method.

Corrected an error in the definition of eta.

This change had been made on the 1.2 line, but was also needed on the 1.3 line.
See r6611 (http://svn.gna.org/viewcvs/relax?rev=6611&view=rev) for details.

Updated a copyright.