relax SVN archive

Split out the molecule, residue and spin container code into its own module.

Shifted the spin viewer window code into its own package.

Renaming and rearrangement of the methods of the Container class.

Renaming and clean up of the Mol_res_spin_tree methods.

Created right click select and deselect menu entries for the molecules, residues and spins.

Added the select and deselect user function menus to the spin viewer window.

All of the select and deselect user function pages are now initialised.

Created all of the deselect user function pages by copying the select module.

Created all the select user function pages.

The structure.load_spins user function page spin_id_element() call defaults to '@N'.