This fixes the output gliches visible in the previous patches,
where highlighting a state would remove its fill color.
* spot/twaalgos/dot.cc, spot/taalgos/dot.cc: Implement option C(COLOR).
* bin/common_aoutput.cc, doc/org/oaut.org: Document it.
* doc/org/.dir-locals.el.in, doc/org/init.el.in,
python/spot/__init__.py: Use it.
* tests/python/automata-io.ipynb, tests/python/automata.ipynb,
tests/python/highlighting.ipynb: Test it.
* tests/core/readsave.test: Adjust.
* NEWS: Mention recent changes.
* spot/twaalgos/dot.cc: Implement it.
* spot/taalgos/dot.cc: Ignore it.
* spot/twaalgos/copy.cc, spot/twaalgos/copy.hh: Add option
to limit the number of states.
* tests/python/ltsmin.ipynb: Improve test case.
* tests/Makefile.am: Cleanup the files generated by ltsmin.ipynb.
* python/spot/__init__.py (setup): Add a max_states argument
that default to 50.
* bin/common_aoutput.cc: Mention the <INT option.
* NEWS: Likewise.
* python/spot/ltsmin.i: New file.
* python/Makefile.am: Add it.
* python/spot/impl.i: Add bindings for kripke and fair_kripke.
* tests/python/ltsmin.ipynb: New file.
* tests/Makefile.am, doc/org/tut.org: Add it.
* tests/python/ipnbdoctest.py: Make it possible for notebook
to exit(77).
* debian/control: Make the Python package dependent
on libspotltsmin0.
* python/spot/__init__.py: Typo.
