* src/tgbaalgos/remprop.cc, src/tgbaalgos/remprop.hh: New files.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgbatest/remprop.test: New test.
* src/tgbatest/Makefile.am: Add it.
* src/bin/autfilt.cc: Implement the option.
* doc/org/autfilt.org: Document it.

It makes more sense to assume that the removed set cannot be visited.

* src/tgbaalgos/mask.cc: Flip a Boolean.
* src/tgbatest/maskacc.test: Adjust test case.
* doc/org/autfilt.org: Add an example.

* src/tgba/tgbagraph.cc (purge_dead_states): Using a DFS to compute a
topological order, allowing to remove useless using a second
pass (instead of iterating the passes until there is nothing to remove).
* src/tgbaalgos/remfin.cc: Call purge_dead_states().
* src/tgbatest/remfin.test, src/tgbatest/det.test: Adjust expected
output.
* doc/org/autfilt.org: Update example.

* doc/org/oaut.org: Some typos.
* doc/org/autfilt.org: Add some examples.

This implement several new options for --dot in order to
allow emptiness sets to be output as colored ⓿ or ❶...
Also add a SPOT_DOTDEFAULT environment variable.

* NEWS, src/bin/man/spot-x.x, src/bin/common_aoutput.cc,
src/bin/dstar2tgba.cc: Document the new options.
* doc/org/.dir-locals.el, doc/org/init.el.in: Setup
SPOT_DOTEXTRA and SPOT_DOTDEFAULT for all documents.
* doc/org/autfilt.org, doc/org/dstar2tgba.org, doc/org/ltl2tgba.org,
doc/org/ltldo.org, doc/org/oaut.org, doc/org/randaut.org,
doc/org/satmin.org: Adjust to this new setup.
* src/misc/escape.cc, src/misc/escape.hh (escape_html): New function.
* src/tgba/acc.cc, src/tgba/acc.hh (to_text, to_html): New method.
* src/tgbaalgos/dotty.cc: Implement the new options.
* src/tgbatest/readsave.test, wrap/python/tests/automata.ipynb: More
tests.
* wrap/python/spot.py: Make sure the default argument for
dotty_reachable is None, so that SPOT_DOTDEFAULT is honored.

* doc/org/oaut.org: Mention --dot=a.
* doc/org/autfilt.org: Update list of transformations.

* src/bin/autfilt.cc: Tweak --help.
* doc/org/autfilt.org: More documentation.

* doc/org/autfilt.org, doc/org/csv.org, doc/org/dstar2tgba.org,
doc/org/genltl.org, doc/org/ioltl.org, doc/org/ltl2tgba.org,
doc/org/ltlfilt.org, doc/org/ltlgrind.org, doc/org/oaut.org,
doc/org/randaut.org, doc/org/tools.org: Update.

* doc/org/setup.org: New file.
* doc/Makefile.am: Distribute it.
* doc/org/autfilt.org, doc/org/csv.org, doc/org/dstar2tgba.org,
doc/org/genltl.org, doc/org/ioltl.org, doc/org/ltl2tgba.org,
doc/org/ltl2tgta.org, doc/org/ltlcross.org, doc/org/ltlfilt.org,
doc/org/ltlgrind.org, doc/org/oaut.org, doc/org/randaut.org,
doc/org/randltl.org, doc/org/satmin.org, doc/org/tools.org: Use
setup.org.

* doc/org/autfilt.org, doc/org/csv.org, doc/org/dstar2tgba.org,
doc/org/genltl.org, doc/org/ioltl.org, doc/org/ltl2tgba.org,
doc/org/ltl2tgta.org, doc/org/ltlcross.org, doc/org/ltlfilt.org,
doc/org/ltlgrind.org, doc/org/oaut.org, doc/org/randaut.org,
doc/org/randltl.org, doc/org/satmin.org, doc/org/tools.org: Here.

* doc/org/oaut.org: New file.
* doc/Makefile.am: Add it.
* doc/org/autfilt.org, doc/org/ltl2tgba.org, doc/org/randaut.org,
doc/org/tools.org: Link to it.

* NEWS: Mention these tools.
* doc/org/autfilt.org, doc/org/randaut.org: New files.
* doc/org/tools.org, doc/Makefile.am: Add them.