relax SVN archive

Added the rudimentary beginnings of the molecule user function class.

Implemented the generic_fns.residue.renumber() function and fixed its unit tests.

Created the generic_fns.residue.rename() function and fixed the corresponding unit tests.

Added 3 unit tests for the non-existant residue.renumber() function.

Fixed a bug in the 'test_rename' unit test.

Added a unit test for renaming multiple residues simultaneously through 'residue.rename()'.

Removed the 'residue.merge()' from the data model redesign document.

I cannot see the purpose of this function, as it would probably duplicate the functionality of
'residue.copy()' function. It was first mentioned by Chris MacRaild in the post at
https://mail.gna.org/public/relax-devel/2006-10/msg00061.html.

Added two unit tests for the, as of yet, non-existent 'generic_fns.residue.rename()' function.

Removal of the 'tensor_pdb' branch which was merged back into the 1.3 line at r2847 in 2006-11-15.

Removal of the 'error_import' branch.

This branch was merged back into the 1.3 line back at r3074, in 2007-03-04.