relax SVN archive

Fix for bug #12437 (https://gna.org/bugs/?12437).

The problem was that the 'from_xml' and 'to_xml' methods needed to be blacklisted to prevent them
from being restored from the pickled state.

Fix for the theta and phi angle checks in the test_palmer_omp() system test.

Fix for the setting of the theta and phi diff tensor angles from the Modelfree4 mfout file.

The angles need to be passed in in radian units.

Reverted r7677. This was a false alarm!

The command used was:
svn merge -r7677:7676 .

Fix for the backend of the dx.execute() user function.

The file arg was at some point renamed to file_prefix. The code now uses this name change.

Bug fix for the dx.execute() user function - the correct args now are used.

Fixes for the OpenDX code to handle mapping of the global parameter space (diff tensor, etc.).

Important bug fix!!

The theta angle of the spheroidal diffusion tensor was being improperly wrapped between 0 and pi.
This was causing the glide reflection symmetry to be broken, hence the tensor was incorrect. The
result would be longer optimisation times for the spheroid tensors and more iterations than
necessary in the full_analysis.py script.

The spheroidal diffusion tensor from the mfout file is now read and loaded into the relax data store.

Fix for the spin names in the test_palmer_omp() system test checks.