* spot/twaalgos/dot.cc (print_dot): Add some detection of Mealy
machines, and some code to render its I/O in a <table>.
* tests/python/synthesis.ipynb: Adjust expected output.
* tests/python/_mealy.ipynb: New file.
* tests/Makefile.am: Add python/_mealy.ipynb.
* NEWS: Mention the new feature.
