relax SVN archive

Initialized merge tracking via "svnmerge" with revisions "1-17738" from
svn+ssh://bugman@.../svn/relax/branches/tensor_data

Initialized merge tracking via "svnmerge" with revisions "1-17737" from
svn+ssh://bugman@.../svn/relax/trunk

Mass conversion of the alignment tensor data structures to the same new design as the diffusion tensor.

This large set of changes matches all of those revisions for the diffusion tensor already committed in
this branch. The alignment tensor data structures are now read only, and can only be modified via the
set() method. This is a much simplified design which works on all Python versions.

Small clean ups of the diffusion tensor data structure code.

Deleted the now unused _update_sim_set() method of the diffusion tensor data structure.

Removed the now unused _update_sim_append() method from the diffusion tensor data structure.

Cleaned up the docstring of the diffusion tensor data object __setattr__() method.

Updated all of the diffusion tensor unit tests to the new design.

Fix for the reading of model-free results files from relax 1.2 when simulation data is missing.

Fix for the reading of relax 1.2 model-free results files for the diffusion tensor structure redesign.