relax SVN archive

Bug fix for the arg_check.is_none() function - the RelaxNoneError was not imported!

Added an initial attempt at the frame order auto-analysis protocol code.

Initialized merge tracking via "svnmerge" with revisions "1-15012" from
svn+ssh://bugman@.../svn/relax/1.3

Creating a branch for playing and extending the frame order theory.

Created a new algorithm for finding the pivot of motion between different structural models.

This is available through the structure.find_pivot user function.

Fix for the numbering of the TER record and subsequence HETATM records in the PDB file creation.

The structure.write_pdb user function now creates the correct TER record after the ATOM records,
and the HETATM records are renumbered if needed.

Added the validate_models() method to the structural API.

This is used to check that the models are 100% consistent.

Added the centroid argument to the structure.superimpose user function.

This allows for the superimposition of structures assuming a pivoted motion.

Another fix for the print out of the structure.superimpose user function.

The final step of calculating the displacements to the final mean structure was incorrectly output.
This has no effect on the algorithm.

Fix for the structure.superimpose user function print outs - the angle is now in degrees.