scc_filter_states: also remove useless acceptance marks

* src/twaalgos/sccfilter.hh,
src/twaalgos/sccfilter.cc (scc_filter_states): Remove useless acceptance
marks while preserving state-based acceptance.  Add a new argument
to specify if all useless mark have to be removed, like for scc_filter.
* src/twaalgos/simulation.cc: Use the new parameter.
* src/twaalgos/postproc.cc: Likewise.  Also call do_scc_filter even
after WDBA simplification to cleanup trivial SCCs.  Preserve state-based
acceptance for weak automata.
* src/tests/readsave.test: Add one test.
* src/tests/dstar.test, src/tests/prodor.test, src/tests/remfin.test,
src/tests/sim3.test, wrap/python/tests/automata.ipynb,
wrap/python/tests/piperead.ipynb: Adjust expected output.
* NEWS: Mention the change.

src/tests/readsave.test

@@ -700,3 +700,40 @@ diff output3 expect3
 
 $autfilt -Hk input 2>stderr && exit 1
 grep 'print_hoa.*k' stderr
+
+cat >input4 <<EOF
+HOA: v1
+States: 3
+Start: 0
+AP: 2 "a" "b"
+Acceptance: 2 Inf(0) & Inf(1)
+--BODY--
+State: 0 {0}   [0] 1
+State: 1 {1}   [1] 2
+State: 2 {0 1} [0] 2
+--END--
+EOF
+
+$autfilt -H --small --high input4 >output4
+cat output4
+
+cat >expect4<<EOF
+HOA: v1
+States: 3
+Start: 1
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: trans-labels explicit-labels state-acc deterministic
+properties: inherently-weak
+--BODY--
+State: 0
+[1] 2
+State: 1
+[0] 0
+State: 2 {0}
+[0] 2
+--END--
+EOF
+
+diff output4 expect4