autfilt: add new option --accept-word

Suggested by Matthias Heizmann. Fixes #109.

* NEWS: notify the new option
* THANKS: add Matthias Heizmann
* bin/autfilt.cc: add new option --accept-word=WORD which filters
automata that accept WORD
* doc/org/autfilt.org: add an example of the new option
* tests/Makefile.am: add core/acc_word.test to the list of test files
* tests/core/acc_word.test: test some uses of the new option

tests/Makefile.am

@@ -277,7 +277,8 @@ TESTS_twa = \
   core/ltlcross2.test \
   core/complementation.test \
   core/randpsl.test \
-  core/cycles.test
+  core/cycles.test \
+  core/acc_word.test
 
 
 ############################## PYTHON ##############################

tests/core/acc_word.test

@@ -0,0 +1,27 @@
+#!/bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2016 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/>.
+
+
+# The --accept-word option filters automata that accept the given word
+# If several words are given, it filters automata that accept ALL words
+ltl2tgba 'G!a' | autfilt --accept-word 'b; cycle{!a}'
+ltl2tgba 'a U b' | autfilt --accept-word 'a; a; cycle{b}'
+ltl2tgba 'F(!a&b)' |
+    autfilt --accept-word 'b; cycle{b; !a&b}' --accept-word 'cycle{b}'