relax SVN archive

Created the new Interatomic system test class for testing out the interatomic data containers.

Reverted the CaM synthetic randomised data change of r17071, as the data randomisation shouldn't change.

The commands used were:
svn merge -r17071:r17070 synth_rdc_rand
svn merge -r17071:r17070 synth_pcs_rand

Another interatomic data design fix for the N_state_model.test_pcs_to_rdc system test.

Fix for the dipole_pair.unit_vectors user function - the vector averaging now occurs after the normalisation.

Fix for the N_state_model.test_metal_pos_opt system test.

Interatomic data design fix for the N-state model analysis _minimise_bc_data() method.

Fix for the lactose N-state model system test script for the interatomic data design.

The interatomic CH2 vectors are now deselected.

Fixes for the N_state_model.test_pcs_to_rdc system test for the interatomic data design.

Fix for the rdc.write user function backend.

The data is now properly formatted for the relax_io.write_data() function.

Shifted the InteratomContainer.id_match() method into the generic_fns.interatomic module.

This is needed to allow the correct data pipes to be matched.