* wrap/python/spot.py: Introduce spot.translate (and
spot.formula.translate) as well, as a wrapper around the
spot.translator class.  Also implement spot.tgba.show()
to allow passing argument to dotty_reachable() before
the result is converted to SVG.
* wrap/python/tests/automata.ipynb: New test file.
* wrap/python/tests/Makefile.am: Add it.