* src/tests/safra.cc: Output error message for wrong ltl formula.
* src/twaalgos/safra.cc: Default comparision of vector does not
correspond to the desired comparision.
* src/tests/safra.cc, src/tests/safra.test: Use HOA format in tests.
* src/twaalgos/safra.cc: Make sure the number of sets are always odd so
that cycles without any acceptance set are rejected.
* src/tests/safra.cc, src/tests/safra.test: Update results.
* src/twaalgos/safra.cc, src/twaalgos/safra.hh: The use of transitions
resulted in non deterministic automata. By using sub-transitions the
problem is solved.
