python: add wrapper for libspotgen

For #254.

* python/spot/gen.i, tests/python/gen.py: New files.
* python/Makefile.am, tests/Makefile.am: Adjust.
* NEWS: Mention the spot.gen python package.

python/spot/gen.i

@@ -0,0 +1,53 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2017 Laboratoire de Recherche et Développement de
+// l'Epita (LRDE).
+//
+// 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/>.
+
+%{
+  // Workaround for SWIG 2.0.2 using ptrdiff_t but not including cstddef.
+  // It matters with g++ 4.6.
+#include <cstddef>
+%}
+
+%module(package="spot", director="1") gen
+
+%include "std_string.i"
+%include "exception.i"
+%include "std_shared_ptr.i"
+
+%shared_ptr(spot::twa_graph)
+
+%{
+#include <spot/gen/automata.hh>
+using namespace spot;
+%}
+
+%import(module="spot.impl") <spot/misc/common.hh>
+%import(module="spot.impl") <spot/tl/formula.hh>
+%import(module="spot.impl") <spot/twa/fwd.hh>
+
+%exception {
+  try {
+    $action
+  }
+  catch (const std::runtime_error& e)
+  {
+    SWIG_exception(SWIG_RuntimeError, e.what());
+  }
+}
+
+%include <spot/gen/automata.hh>