relax SVN archive

Bug fix for the __set_diff_tensor() method for reading the tensor from a relax 1.2 results file.

This was uncovered by searching for the relax data store. This store rather than the current data
pipe was being accessed. The additional large bug found is that the diffusion tensor was referred
to as 'diff' rather than 'diff_tensor'.

Removed the dependence on the relax data store.

Created the pipes API function pipe_names() to get the list of all data pipes.

Converted the back_calc() function to the new relax design.

Shifted the reset() functional code to generic_fns.

Removed the dependence on the relax data store by using the pipes API.

Created the has_pipe() function for the pipes API.

Updated the latex_mf_table.py sample script to the new design.

The problems were identified with the import of the relax data storage object.

Documentation fix in the sample script.

Converted the relax_curve_diff.py sample script to the new design.

This was identified by the unnecessary import of the relax data storage object.