relax SVN archive

Converted the old diffusion tensor __setattr__() method into the set() method.

This is the only way in which diffusion tensor parameters, errors and simulations can be set.

Renamed the diffusion tensor data structure type() method to set_type().

This is because the type is stored as the 'type' object, clashing with the method name.

Created the diffusion tensor data structure type() method for setting the tensor type.

This is to remove the "cdp.diff_tensor.type = 'x'" code from the core of relax, as the structure is
now read only.

The new diffusion tensor fixed() method has been created to allow the fixed flag to be changed.

Fix for the initialisation of the diffusion tensor data structure, now that it is read-only.

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.