relax SVN archive

Fixed the test for if a structure has been loaded in the centre_of_mass() function.

Added a test for a loaded structure to the generic_fns.structure.centre_of_mass() function.

Bug fix in the generic_fns.structure.centre_of_mass() function.

The variable 'cdp' did not exist.

Fixed the n_state_model.CoM() user function to allow the centre arg to be None.

Modified the pivot_point arg test of the n_state_model.CoM() user function.

The arg value of None is not allowed.

Fixed the pivot_point arg test of the n_state_model.CoM() user function.

This was using the now non-existant n_state_model.pivot_point() user function.

Compacted the printed out messages from the n_state_model.CoM() user function.

Change of format in the reporting of the cone order parameters.

The diffusion on a cone order parameter (second Legendre poly of the cone angle) is now calculated.

Renamed the cone angle variables.