relax SVN archive

Syntax error fix.

The N-state model specific analysis code is now handling RDCs as interatomic data.

This still has a lot of work before it will be functional.

Started to convert the N-state model optimisation code to handle RDCs as interatomic data.

Created the generic_fns.interatomic.interatomic_loop() generator function.

Lots of updates to the rdc.read user function backend.

Fix for the id_match() method - there are no indices.

Shifted the id_match() method to the correct class!

Updated another N-state model system test script to the new rdc.read interatomic data design.

The generic_fns.interatomic.create_interatom() function now returns the created container.

This comes from the InteratomicContainer.add_item() method which now also returns the container.

Missing imports.