relax SVN archive

The diffusion tensor data structure has been completely converted into a read-only structure.

The __setattr__() method now will always raise a RelaxError, and the diffusion tensor simulation
data structure objects __setitem__() method will raise the same error.

Creating a branch to redesign the diffusion and alignment tensor data structures for Python 3.

Updated the relax version numbers and 'trunk' used relax user manual.

For example the information about checking out the main development line was still talking about 1.3
rather than the trunk.

Fix for the fix of r17734 which attempted to fix r17733.

The Python version is now being detected.

Removed some debugging printouts accidentally committed in r17734.

The fix of r17733 actually broke Python 2.

The list.__setattr__() method is fundamentally different between Python 2 and 3!

Python 3 fix for the setting of diffusion and alignment tensor simulation values.

The previous code somehow worked in Python 2 but was not formally correct and broke in Python 3.

Python 3 fix for the model-free results file reading tests.

The ordering of dictionaries is different in Python 3, so now these are properly converted from
strings to dictionaries before comparison. This was not happening because of the XML changes from
Python 2.7.3 onwards.

The relaxation curve-fitting system tests are now skipped if the module is missing or broken.

This improves the printouts from the test suite and shows a summary of skipped tests rather than a
pile of traceback messages and errors.

The messsage about skipping the GUI tests due to wxPython being missing is now more specific.

This was being shown for all runs of the test suite when it only needs to appear if GUI tests have
been run.