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/parseaut/parseaut.yy, spot/parseaut/scanaut.ll:
Parse "spot.highlight.edges" and "spot.highlight.states" to
fill the "highlight-edges" and "highlight-states" properties.
* spot/twaalgos/dot.cc: Use these properties to highlight states.
* tests/core/readsave.test: Add a small test.
Fixes#134.
* spot/twaalgos/dot.cc: Implement it.
* bin/common_aoutput.cc, spot/twaalgos/dot.hh, NEWS: Document it.
* tests/core/readsave.test, tests/python/ltsmin.ipynb: Test it.
* bin/common_aoutput.cc, bin/common_aoutput.hh, bin/common_setup.cc:
Implement it.
* NEWS, bin/man/spot-x.x: Document it.
* tests/core/readsave.test: Test it.
This is so that we can have -d as an alias for --dot everywhere.
* bin/randaut.cc: Rename -d as -e.
* NEWS: Mention the change.
* doc/org/autfilt.org, doc/org/oaut.org, doc/org/randaut.org,
tests/core/parseaut.test, tests/core/readsave.test: Adjust.
