Consider adding bonded neighbor to hydrogen rotators

[russell-taylor]

When a hydrogen rotates around a heavy atom, it can shield that atom from clashes in addition to making hydrogen bonds with neighbors. If we add the bonded neighbor from the hydrogen(s) in rotatable hydrogens, this will be taken into account.

@todo: A trial addition of this caused much slower optimization for cliques (see, for example, 4fen) because of the additional work checking dots on these atoms, so we should probably only add this if we can make the dot-collision code much faster.

[russell-taylor]

Actually, this is present in the original reduce -- they atoms are added during the test for clashes. So this needs to be put back in.

[russell-taylor]

Fixed by reverting these changes.