unsigned int OEBondGetSmallestRingSize(const OEBondBase &bnd)
Determine the size of the smallest ring that a bond is in. The
function OEFindRingAtomsAndBonds
should have been called before
calling this function. If the bond is not in a ring, i.e.
OEBondBase::IsInRing
returns false, the value zero is returned.