sat-minimize: some documentation and associated fixes

* doc/org/satmin.org: Document the new DTωA-minimization procedure.
* doc/org/tools.org: Fix link.
* src/bin/autfilt.cc: Pass -S to sat_minimize().
* src/twa/twagraph.hh: (state_acc_sets) New method.
* src/twaalgos/dotty.cc: Use it to correctly display co-Büchi automata.
* src/twaalgos/dtbasat.cc: Set the deterministic property on the result.
* src/twaalgos/dtgbasat.cc: Likewise, and preprocess the input automaton
in sat_minimize().
* src/twaalgos/dtgbasat.hh: Fix documentation, and take the state-based
information as an argument.
* src/twaalgos/postproc.cc: Do not call simulation-based reduction
on non-separated acceptances.
* src/tests/satmin2.test: Use -S rather than 'state-based'.
* NEWS: Update.

src/twaalgos/postproc.cc

@@ -32,6 +32,7 @@
 #include "complete.hh"
 #include "totgba.hh"
 #include "sbacc.hh"
+#include "sepsets.hh"
 
 namespace spot
 {
@@ -93,6 +94,8 @@ namespace spot
   twa_graph_ptr
   postprocessor::do_simul(const twa_graph_ptr& a, int opt)
   {
+    if (!has_separate_sets(a))
+      return a;
     switch (opt)
       {
       case 0: