virtual OEAtomBase *GetEnd() const
Return the ``end'' (or ``destination'') atom of a bond. The end atom
of a bond is defined either when the bond is created with
OEMolBase::NewBond
, or possibly by a call to the
OEBondBase::SetEnd
method. If the end atoms was specified as
the NULL pointer, (OEAtomBase*)0, when the bond was created, this
method may return a NULL pointer.