Changing the thresholds to be bigger in the previous patch isn't

Changing the thresholds to be bigger in the previous patch isn't
really useful unless we simultaneously change the per-iteration deltas
to be smaller.  Add another pseudo-tunable to control the speed with
which we change values across iterations.  As it turns out, this is
much more effective than the threshold tunable.  It does come at the
cost of lower solution performance, however.