relax SVN archive

Updated the http://www.nmr-relax.com/download.html webpage for the relax 4.0.1 release.

Backported the relax 4.0.1 CHANGES file changes to trunk.

The command used was:
svn merge -r28142:28143 svn+ssh://bugman@.../svn/relax/tags/4.0.1 .

Updated the CHANGES file for relax 4.0.1.

Added the relax 4.0.1 PDF manual to the repository.

Updated the relax version number to 4.0.1.

relax version 4.0.1.

This is a major feature and bugfix release. Features include the new structure.pca user function
for performing a principle component analysis (PCA) of a set of structures, handling of replicated
R2eff data points in the dispersion analysis, improvements in the handling of PDB structures, the
protection against numpy >= 1.9 FutureWarnings for a number of soon to change behaviours in numpy,
and addition of a deployment script for the Google Cloud Computing. Bugfixes include an error when
loading relaxation data, the CSA constant equation in the manual, missing information in the relax
state and results files, loading of certain state files in the GUI, running relax with no graphical
display and using matplotlib, BMRB export failure when a spin container is missing data or
parameters.

Set up more redirects for incorrectly linked user function pages.

Fix for the Mf.test_bug_24131_missing_interaction system test.

This is part of bug #24131 (https://gna.org/bugs/?24131), the BMRB export failure with the
SpinContainer object having no s2 value. The problem was when assembling the diffusion tensor data.
The spin_loop() function was being called, as the diffusion tensor is reported for all residues.
Therefore the skip_desel=True has been added to match the model-free part.

Added the Mf.test_bug_24131_missing_interaction system test to catch another problem.

This is part of bug #24131 (https://gna.org/bugs/?24131), the BMRB export failure with the
SpinContainer object having no s2 value. However the previous fix of skipping deselected spins
introduced a new problem of relax still searching for the interatomic interactions for that
deselected spin.

Another fix for bug #24131 (https://gna.org/bugs/?24131).

This is the BMRB export failure when the SpinContainer object has no s2 attribute. Now no data is
stored in the BMRB file if a model-free model has not been set up for the spin. This allows the
test suite to pass.