twaalgos: Implement language_map algo

* python/spot/impl.i: Add python bindings.
* spot/twaalgos/langmap.cc: Implement algo.
* spot/twaalgos/langmap.hh: Declare algo.
* spot/twaalgos/Makefile.am: Add new files.
* tests/python/langmap.py: Add tests.
* NEWS: Update.

spot/twaalgos/langmap.hh

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+// -*- coding: utf-8 -*-
+// Copyright (C) 2016 Laboratoire de Recherche et Développement de l'Epita.
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include <vector>
+#include <spot/twa/twagraph.hh>
+
+namespace spot
+{
+  /// \brief Identify states that recognize the same language.
+  ///
+  /// The returned vector is the same size as the automaton's number of state.
+  /// The number of different values (ignoring occurences) in the vector is the
+  /// total number of recognized languages, states recognizing the same
+  /// language have the same value.
+  ///
+  /// The given automaton must be deterministic.
+  SPOT_API std::vector<unsigned>
+  language_map(const const_twa_graph_ptr& aut);
+
+  /// \brief Color automaton's states that recognize the same language.
+  SPOT_API void
+  highlight_languages(twa_graph_ptr& aut, const std::vector<unsigned>& v);
+}