* spot/twaalgos/isweakscc.cc, spot/twaalgos/isweakscc.hh,
spot/twaalgos/mask.cc, spot/twaalgos/mask.hh: Adjust to
work with alternating automata.
* spot/twaalgos/sccinfo.cc, spot/twaalgos/sccinfo.hh
(determine_unknown_acceptance): Do not complain about
not supporting alternating automata if there is not
indeterminate acceptance.
* spot/twaalgos/stats.cc: Fix a bug were %[iw]c was
read as %[iww]c.
* tests/core/alternating.test: Test is_inherently_weak_scc() and
is_weak_scc().
* python/spot/impl.i: Add missing python bindings
for isweakscc.hh.