* src/ltlvisit/lunabbrev.cc, src/ltlvisit/lunabbrev.hh,
src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh,
src/ltlvisit/wmunabbrev.cc, src/ltlvisit/wmunabbrev.hh: Delete.
* src/ltlvisit/unabbrev.cc, src/ltlvisit/unabbrev.hh: New files.
* src/ltlvisit/Makefile.am: Adjust.
* src/ltlvisit/print.cc, src/tests/equalsf.cc, src/tests/Makefile.am,
src/twaalgos/ltl2taa.cc, wrap/python/spot_impl.i, src/bin/ltlfilt.cc:
Adjust callers.
* src/ltlvisit/contain.cc, src/tests/syntimpl.cc: Remove useless
include.
* wrap/python/tests/formulas.ipynb: New test cases.
* doc/tl/tl.tex: Group all rules in a single section.
* NEWS: Mention it.