Add the "don't care" simulation

* src/tgba/bddprint.cc, src/tgba/bddprint.hh: Add bdd_print_isop
that prints the bdd into a Irreductible Sum Of Product.
* src/tgbaalgos/dupexp.cc, src/tgbaalgos/dupexp.hh: Add a way to
know which states (in the input) is which (in the result).
* src/tgbaalgos/simulation.cc, src/tgbaalgos/simulation.hh: Add
the Don't Care Simulation and the Don't Care Iterated Simulation.
* src/tgbatest/ltl2tgba.cc, src/tgbatest/spotlbtt.test,
src/tgbatest/Makefile.am, src/tgbatest/sim.test: Test them.
* bench/ltl2tgba/algorithms, bench/ltl2tgba/README,
bench/ltl2tgba/algorithms: Add a way to bench the don't care
simulation.

src/tgba/bddprint.hh

@@ -113,6 +113,23 @@ namespace spot
 
   /// \brief Enable UTF-8 output for bdd printers.
   void enable_utf8();
+
+
+  /// \brief Format a BDD as an irredundant sum of product.
+  /// \param dict The dictionary to use, to lookup variables.
+  /// \param b The BDD to print.
+  /// \return The BDD formated as a string.
+  std::string
+  bdd_format_isop(const bdd_dict* d, bdd b);
+
+
+  /// \brief Print a BDD as an irredundant sum of product.
+  /// \param os The output stream.
+  /// \param dict The dictionary to use, to lookup variables.
+  /// \param b The BDD to print.
+  std::ostream&
+  bdd_print_isop(std::ostream& os, const bdd_dict* d, bdd b);
+
 }
 
 #endif // SPOT_TGBA_BDDPRINT_HH