* spot/twaalgos/strength.cc, spot/twaalgos/strength.hh
(is_inherently_weak_automaton): New function.
(is_type_automaton): Adjust to implement the above and
set prop_inherently_weak().
* spot/twaalgos/isweakscc.cc, spot/twaalgos/isweakscc.hh:
Rewrite is_inherently_weak_scc() to not enumerate cycles.
* spot/bin/autfilt.cc: Add a --is-inherently-weak option.
* spot/tests/readsave.test: More tests.
* spot/tests/strength.test: Adjust expected output.
* doc/org/hoa.org: Adjust documentation of --check.
* NEWS: Mention those changes.
1f2260f971