Extending function isMoleculeForbidden()

Because of the many new molecular structures possible by accounting for
lone electron pairs, such as ions and new forms of radicals, we have to
forbid, at least at the moment, certain structures until we have more
thermodynamic and kinetics information for them in our libraries.

- Until we have more thermodynamic data of charged molecules we will
forbid them
- We also forbid positively charged oxygen atoms
- We forbid at least at the moment oxygen atoms with bond order larger
than two and radical oxygen with a bond order of two