* spot/twaalgos/dot.cc: Add support for option 'E', and default to
rectangle nodes for large labels.
* bin/common_aoutput.cc, NEWS: Document it.
* tests/core/alternating.test, tests/core/dstar.test,
tests/core/readsave.test, tests/core/sccdot.test,
tests/core/tgbagraph.test, tests/python/_product_weak.ipynb,
tests/python/alternation.ipynb, tests/python/atva16-fig2b.ipynb,
tests/python/automata.ipynb, tests/python/decompose.ipynb,
tests/python/gen.ipynb, tests/python/highlighting.ipynb,
tests/python/ltsmin-dve.ipynb, tests/python/ltsmin-pml.ipynb,
tests/python/parity.ipynb, tests/python/pdegen.py,
tests/python/satmin.ipynb, tests/python/stutter-inv.ipynb: Adjust all
test cases.
