relax SVN archive

Changed the name of the model_num arg to model in the centre_of_mass() function.

Added the atom ID argument to the structure.rotate and structure.translate user functions.

This allows subsets of molecules or models to be translated and rotated.

The generic_fns.structure.mass.centre_of_mass() function now accepts the model number arg.

This allows specific models to be isolated.

The generic_fns.structure.mass.centre_of_mass() function now accepts the atom ID arg.

This allows the centre of mass of subsets of the structure to be calculated.

Fix for the negative cone PDB representation in the frame order theory.

Fixes for the negative cone creation in the frame_order.cone_pdb user function.

Created the Frame_order.test_cam_iso_cone_free_rotor2 system test.

This is the isotropic cone, free rotor frame order model with a tilted central axis.

Implemented the Frame_order.test_cam_iso_cone_free_rotor system test.

Fix for the iso_cone_free_rotor.py system test script.

The average position alpha Euler angle is not defined in this model.

Fixes for the free rotor frame order model system test scripts.

The average position alpha Euler angle is not defined in these models!