Ell authored Jan 08, 2016 and Michael Natterer committed Jan 17, 2016

...gimp_pickable_contiguous_region_by_seed(), in preperation
for adding a similar option to the relevant tools.

When this parameter is TRUE, all eight neighbors of each pixel
are considered when calculating the resulting region, instead
of just the four orthogonal ones.

This commit also modifies all callers to pass FALSE for this
parameter, to retain the current behavior.