Modifying the scheme for filtering of local minima to regional minima by
rDisk. Rather than looking at the neighborhood of each localMin, we now
compare all localMin to each other. Note that this scales badly as the
number of localMin increases wrt grid size or rDisk.

There are a few other misc. additions.
Now testing on a summer2006 case. Unclear why there's still a problem
with duplicate values when following the steepest descent to a cellIsMin