Add Footprint method to merge with neighbors
add mergeFootprits() function to afwDet
mergeFootprints() is passing tests, with overly complex algorithm
use simpler algorithm for mergeFootprints()
remove printfs and put 'if False' around plots
merge connected spans; also require normalized footprints
add checkNormalized(); don't call normalize() and instead set _normalized=true in mergeFootprints().
add Footprint.addSpanInSeries(), and Footprint.clipToNonzero()
add test case for Footprint.clipToNonzero and find the bug (was making a copy of spanlist -- ugh!)
make mergeFootprints non-member functions
argh, footprint.clipToNonzero denormalizes!
fix peak lists in mergeFootprints() -- dumb missing reference &
minor: remove peak debugging
add nearesteFootprint() function; instantiate a broader range of Footprint functions for int images