Add Footprint method to merge with neighbors
Merge branch 'u/jbosch/DM-340'
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