combineAtomsParams

Combines together atoms params from two variations of the same molecule. Useful for eg applying two mutations to the same molecule. If the two atoms parameters disagree on params for an atom, the tie should be broken by picking the atom params from the atoms params whose given atom indices contain the disagreeable atom's index. The two given sets of atom indices should not overlap. If a tie can't be broken with the preferred atom indices, the implementation should throw an exception.