* bin/common_aoutput.cc: Make HOA the default output.
* NEWS: Mention this.
* doc/org/autfilt.org, doc/org/dstar2tgba.org, doc/org/hoa.org,
doc/org/ltl2tgba.org, doc/org/ltl2tgta.org, doc/org/ltlcross.org,
doc/org/ltldo.org, doc/org/oaut.org, doc/org/randaut.org,
doc/org/satmin.org, doc/org/tut02.org, doc/org/tut03.org,
doc/org/tut20.org, doc/org/tut21.org, doc/org/tut30.org,
tests/core/dstar.test, tests/core/ltldo2.test, tests/core/monitor.test,
tests/python/piperead.ipynb: Adjust.