relax SVN archive

Fix for the MolList.is_empty() method.

Now if no MolContainers are in the list, the method returns True.

Fix for the ModelList.add_item() method.

If no ModelContainers are present, then don't try to change the model number!

Fix for the ModelList.is_empty() method.

Now if no ModelContainers are in the list, the method returns True.

Added a missing import.

Fixes for the Base_struct_API.from_xml() method.

Regenerated all the results files containing structural info.

Renamed the MolContainer 'mol' element to 'mol_cont'.

This prevents a clash with the pipe container 'mol' structure.

Another fix for __ave_atom_pos(), related to the last!

Fixes for __ave_atom_pos(). The Scientific python data structure is now in MolContainer.data.

Fixes for __residue_loop(). The Scientific python data structure is now in MolContainer.data.