relax SVN archive

Ported r2873 from the 1.2 line.

The command used was:
svn merge -r2872:2873 svn+ssh://bugman@.../svn/relax/1.2

This improves the release checklist.

Improvements to the release checklist.

Fixed a bug in the 'full_analysis.py' script whereby 'run.delete()' was being called.

This was destroying the data required for the convergence tests.

Fixed a bug in the 'full_analysis.py' script for the 1.3 line.

The problem was that task #3838 (https://gna.org/task/?3838) had split the PDB reading user function
from the user function to calculate the unit vector parallel to the XH bond. However the script had
not been updated to call 'structure.vectors()' and hence was not working.

Removed some whitespace.

Bug fix.

This fixes a bug introduced by the changes for task #3838 (https://gna.org/task/?3838). It is also
a partial fix for bug #7544 (https://gna.org/bugs/?7544).

Fixed the parameter convergence test in 'full_analysis.py'.

Bug fix. 'self.relax.generic.structure.read()' was being called when 'read_pdb()' should be.

Changed all the references to the old user function class 'pdb' to 'structure'.

Added a convergence test for the diffusion parameter values to the 'full_analysis.py' script.