relax SVN archive

Added a module docstring to the relax internal PDB structural object.

Included generic_fns/structure/ in the API docs.

Improvements to the generic_fns.structure package docstring.

Added the write_pdb_file prototype method stub to the structral data API.

All the PDB record documentation has been shifted to the API stub method.

A number of docstring updates for the structural data API.

Added the terminate prototype method stub to the structral data API.

Added the atom_connect prototype method stub to the structral data API.

Added the atom_add prototype method stub to the structral data API.

Removed some useless epydoc text.

Updated the internal PDB structural object to use the self.structural_data object.

The atomic_data structure has been replaced by self.structural_data, and is no longer passed into
each method. The description of this object has also shifted from the methods into the class
docstring.