tostring: add LaTeX output

* src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh
(to_latex_string): New function.
* src/bin/common_output.cc, src/bin/common_output.hh:
Add a --latex option.
* doc/tl/spotltl.sty: New file.
* doc/tl/Makefile.am: Distribute it.
* src/ltltest/latex.test: New test.
* src/ltltest/Makefile.am: Add it.
* NEWS: Mention it.

src/ltltest/Makefile.am

@@ -95,6 +95,7 @@ TESTS = \
   kind.test \
   remove_x.test \
   ltlfilt.test \
+  latex.test \
   lbt.test \
   lenient.test \
   isop.test \

src/ltltest/latex.test

@@ -0,0 +1,62 @@
+#!/bin/sh
+# -*- coding: utf-8 -*-
+# Copyright (C) 2013 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/>.
+
+. ./defs
+set -e
+
+# Skip this test if we don't find a sufficiently complete LaTeX
+# installation
+
+(latexmk --version) || exit 77
+(pdflatex --version) || exit 77
+(kpsewhich txfonts.sty) || exit 77
+(kpsewhich amsmath.sty) || exit 77
+
+cat >input <<EOF
+XGFa <-> FGX(!b & !c) | (b ^ a)
+a U b W c R (d & e) M f
+{a;b[=2];((c:d*) && f*);e[*2..]}<>-> {((a | [*0])*;b[+]) & (c1[->2])}[]-> h
+{a;b;c} []=> {d*;e} <>=> !f
+!{a;b*;c}! -> d
+G(uglyname->Fuglierlongname42)
+EOF
+
+(
+cat <<\EOF
+\documentclass{article}
+\usepackage{amsmath}
+\usepackage{spotltl}
+\begin{document}
+\begin{align}
+EOF
+( ../../bin/ltlfilt --latex input;
+  ../../bin/genltl --go-theta=1..3 --latex ) | sed 's/$/\\\\/'
+cat <<\EOF
+\text{done}
+\end{align}
+\end{document}
+EOF
+) > output.tex
+
+TEXINPUTS=$srcdir/../../../doc/tl: latexmk -f -silent --pdf output.tex
+
+# latexmk will have a non-zero exit status on failure, so we will
+# detect that.  However the file output.pdf really ought to be
+# controled by eye...