* NEWS: Mention of the deprecation.
* bin/autfilt.cc, bin/ltlcross.cc, spot/twaalgos/langmap.cc
  spot/twaalgos/minimize.cc, spot/twaalgos/powerset.cc,
  spot/twaalgos/stutter.cc, tests/core/ikwiad.cc,
  tests/python/bugdet.py, tests/python/remfin.py,
  tests/python/sum.py: Refactor calls to dtwa_complement() with calls
  to dualize().
* spot/twaalgos/complement.hh: Adds deprecation notice.