relax SVN archive

Added the frame order free rotor optimisation script and its results.

The structure.read_pdb user function can now handle bzip2 or gzip compressed PDB files.

Calculated the pure RDC tensors for the free rotor CaM frame order model.

Back calculated the RDC and PCS test data from the CaM free rotor frame order model.

The structure.write_pdb user function can now create compressed (bzip2 or gzip) PDB files.

The structure.rotate user function can now operate in individual structural models.

The model keyword argument has been added to allow this.

Created a PDB distribution of CaM orientations for the free rotor frame order model.

This is a uniform set of rotations about the pivot-CoM axis.

Created a data directory for the free rotor CaM test model.

Modified the rigid frame order CaM test model script to properly test the PyMOL representation.

This is not a system test, but is to be used manually and visually to check that the PyMOL
representation created by relax of the average position, eigenframe, and cone is correct!

Created the Frame_order.test_cam_rigid system test and optimisation script.