#4 reporting problematic compounds

[Damjan Krstajic]

In mystructure_set_smiles pairs of compound-ids and
smiles can have one of the following statuses: new
smiles, new ids, old ids and problematic. There is no
action coded if 'problematic' compound appears.
Currently it behaves aas if everything is fine if there
are problematic compounds that haven't been inserted.