relax SVN archive

The fn physical_constants.return_atomic_mass() is now used instead of the old atomic_mass() fn.

Updated physical_constants.return_atomic_mass() to better match generic_fns.structure.atomic_mass().

Created a new directory for the new 'structure' package.

This will eventually contain numerous structure related operations including:

A number of PDB parsers,
A PDB writer,
CIF parsers,
Other structural data file parsers,
Functions for creating geometric objects in structural format,
Mass and inertia related functions.

This package will eventually have a well defined API for accessing structural data independent of
the structure parser used.

Updated the generic_fns.structure.set_vector() function to the new design.

More removal of the run argument as part of the moving to the new design.

More removal of the run argument as part of the moving to the new design.

More removal of the run argument as part of the moving to the new design.

More modifications for the new design and the removal of a 'tab' character.

Reverted revision 5268.

The command used was:
svn merge -r5268:5267 .

Too many errors were present as noted by Edward d'Auvergne in a post at:
https://mail.gna.org/public/relax-devel/2008-04/msg00022.html (Message-id:
<7f080ed10804031148r75a295a2u99569bb13b99ffc5@...>)

More removal of the run argument as part of the moving to the new design.