More intuitive storer-copy/move semantics

More intuitive storer-copy/move semantics

copy/move cont:path path2
   will move all <obj> prefixed with path, as path2<obj>
   or as path2 if path corresponds to just one whole object
copy/move cont:path cont2:
   will move all <obj> prefixed with path to container cont2
copy/move cont:path [cont2:]path2 --exact-match
   will move at most one <obj> as a new object named path2,
   provided path corresponds to a whole object path
copy/move cont:path [cont2:]path2 --replace
   will move all <obj> prefixed with path, replacing path with path2