(re)add explicit =-operator that doesn't copy the needed state
clean up splicing and fix some problems with reindexing clean images
add/fix splcing tests for PropMap
don't hide repeating log messages when running debug code
rename non-const version of PropertyMap::property to touchProperty
add byteswapTest to CTest
build (and test) api_change in travis
Merge branch 'master' into api_change