Using double borders for acceptance states in SBAs.

* src/tgbaalgos/dotty.hh (dotty_reachable): Take a new
assume_sba argument.
* src/tgbaalgos/dotty.cc (dotty_bfs): Take a new
mark_accepting_states arguments.
(dotty_bfs::process_state): Check if a state is accepting using
the state_is_accepting() method for tgba_sba_proxies, or by
looking at the first outgoing transition of the state.  Pass
the result to the dectorator.
(dotty_reachable): Adjust function.
* src/tgbaalgos/dottydec.hh, src/tgbaalgos/dottydec.cc,
src/tgbaalgos/rundotdec.hh, src/tgbaalgos/rundotdec.cc
(state_decl): Add an "accepting" argument, and use it to
decorate accepting states with a double border.
* src/tgbatest/ltl2tgba.cc: Keep track of whether the output
is an SBA or not, so that we can tell it to dotty().
* wrap/python/ajax/spot.in: Likewise.
* wrap/python/cgi-bin/ltl2tgba.in: Likewise.

src/tgbaalgos/dottydec.hh

@@ -1,4 +1,4 @@
-// Copyright (C) 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
+// Copyright (C) 2004, 2011  Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
 // et Marie Curie.
 //
@@ -53,9 +53,12 @@ namespace spot
     /// \param si an iterator over the successors of this state (owned by the
     ///           caller, but can be freely iterated)
     /// \param label the computed name of this state
+    /// \param accepting whether the state is accepting (it makes sense only
+    ///                  for state-acceptance automata)
     virtual std::string state_decl(const tgba* a, const state* s, int n,
 				   tgba_succ_iterator* si,
-				   const std::string& label);
+				   const std::string& label,
+				   bool accepting);
 
     /// \brief Compute the style of a link.
     ///
@@ -86,6 +89,7 @@ namespace spot
   protected:
     dotty_decorator();
   };
+
 }
 
 #endif // SPOT_TGBAALGOS_DOTTYDEC_HH