relax SVN archive

Changed the model arg to struct_index in the structural object API method atom_add().

Deleted all the PDB terminate() function calls and methods.

These are not necessary as the TER record is now automatically generated.

Removed TER from the add_atom() docstring.

The TER record is now automatically created after any ATOM or HETATM stretch.

Fix for the number of hetrogens in the MASTER record.

Improvements to the print outs during PDB creation.

Shifted the ENDMDL record to be before the CONECT records.

Fixes for the hetrogen section.

These records are now correctly created, independent of the number of loaded structures.

Split the PDB creation code into the hetrogen and coordinate sections.

The MODEL and ENDMDL records are now created, if multiple structures exist.