twaalgos/cobuchi: Add nsa_to_nca()

* NEWS: Update.
* spot/twaalgos/cobuchi.hh: Declare to_dca() and nsa_to_nca().
* spot/twaalgos/cobuchi.cc: Implement them.
* python/spot/impl.i: Include new file for python bindings.
* spot/twaalgos/Makefile.am: Add new file.
* bin/autfilt.cc: Add --dca command line option. This option does not
return a deterministic automaton yet, but it will.
* tests/core/dca.test: Add tests for Büchi automata.
* tests/python/dca.py: Add a python script that builds a nondet. Streett
automaton.
* tests/python/dca.test: Add tests for Streett automata.
* tests/Makefile.am: Add all tests.

tests/python/dca.py

@@ -0,0 +1,37 @@
+#!/usr/bin/python3
+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2017 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/>.
+
+import sys
+import spot
+
+
+def gen_streett(formula):
+    aut = spot.translate(formula, 'BA')
+    aut.set_acceptance(2, 'Fin(0) | Inf(1)')
+    for e in aut.edges():
+        if (e.acc):
+            e.acc = spot.mark_t([0,1])
+        else:
+            e.acc = spot.mark_t([0])
+    return aut
+
+
+aut = gen_streett(sys.argv[1])
+print(aut.to_str('hoa'))