Correct LaCIM for ELTL and make it work with LBTT.

* src/eltlparse/eltlparse.yy: Adjust.
* src/ltlast/automatop.cc, src/ltlast/automatop.hh,
src/ltlvisit/clone.cc, src/ltlvisit/nenoform.cc: Clean the way we
handle the negation of automaton operators.
* src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh: Add an
optional argument to output a fully parenthesized string.
* src/tgbaalgos/eltl2tgba_lacim.cc: Fix it.
* src/tgbatest/eltl2tgba.cc: Add a new option (-L) to read formulae
from an LBTT-compatible file.
* src/tgbatest/eltl2tgba.test: A new tests.
* src/tgbatest/spotlbtt.test: Add LaCIM for ELTL.

src/ltlvisit/tostring.hh

@@ -32,14 +32,22 @@ namespace spot
     /// \addtogroup ltl_io
     /// @{
 
-    /// \brief Output a formula as a (parsable) string.
+    /// \brief Output a formula as a string which is parsable unless the formula
+    /// contains automaton operators (used in ELTL formulae).
     /// \param f The formula to translate.
     /// \param os The stream where it should be output.
-    std::ostream& to_string(const formula* f, std::ostream& os);
+    /// \param full_parent Whether or not the string should by fully
+    ///	                   parenthesized.
+    std::ostream&
+    to_string(const formula* f, std::ostream& os, bool full_parent = false);
 
-    /// \brief Convert a formula into a (parsable) string.
+    /// \brief Output a formula as a string which is parsable unless the formula
+    /// contains automaton operators (used in ELTL formulae).
     /// \param f The formula to translate.
-    std::string to_string(const formula* f);
+    /// \param full_parent Whether or not the string should by fully
+    ///	                   parenthesized.
+    std::string
+    to_string(const formula* f, bool full_parent = false);
 
     /// \brief Output a formula as a (parsable by Spin) string.
     /// \param f The formula to translate.