print the right command
do not accept rootdir as masterdir
overlay dirs must be under $masterdir

This is because otherwise the rsync filters won't work
reflect the default values
document parameter color_ok
refuse certain settings of masterdir
badly documented, but hey
on_update is deprecated
always_run is deprecated

Never had any use for it in 10 years time
excluding $masterdir/* gives trouble with alternative config files under $masterdir
scriptdir is deprecated
tasks is deprecated

Maybe too bad, but also a great simplification of synctool. Tasks
always was an oddball feature. Please use dsh / dsh-pkg instead
suggest --numeric-ids
add some explaining
some more explanatory
reflect the default
update WHATSNEW file
obsolete is the correct term
blah