Revert everything related to Damien's work in 2008 (he will commit a new version soon).

Here are the reverted patches:
8c0d1003b0,
25a3114287,
9afbaf6342,
dc0005f4e1,
543190f2bc.

src/ltlast/constant.cc

@@ -0,0 +1,99 @@
+// Copyright (C) 2003, 2005  Laboratoire d'Informatique de Paris 6 (LIP6),
+// département Systèmes Répartis Coopératifs (SRC), Université Pierre
+// et Marie Curie.
+//
+// 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 2 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 Spot; see the file COPYING.  If not, write to the Free
+// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+
+#include "constant.hh"
+#include "visitor.hh"
+#include <cassert>
+
+namespace spot
+{
+  namespace ltl
+  {
+    constant::constant(type val)
+      : val_(val)
+    {
+      switch (val)
+	{
+	case True:
+	  dump_ = "constant(1)";
+	  set_key_();
+	  return;
+	case False:
+	  dump_ = "constant(0)";
+	  set_key_();
+	  return;
+	}
+      // Unreachable code.
+      assert(0);
+    }
+
+    constant::~constant()
+    {
+    }
+
+    void
+    constant::accept(visitor& v)
+    {
+      v.visit(this);
+    }
+
+    void
+    constant::accept(const_visitor& v) const
+    {
+      v.visit(this);
+    }
+
+    constant::type
+    constant::val() const
+    {
+      return val_;
+    }
+
+    const char*
+    constant::val_name() const
+    {
+      switch (val_)
+	{
+	case True:
+	  return "1";
+	case False:
+	  return "0";
+	}
+      // Unreachable code.
+      assert(0);
+      return 0;
+    }
+
+    constant*
+    constant::false_instance()
+    {
+      static constant f(constant::False);
+      return &f;
+    }
+
+    constant*
+    constant::true_instance()
+    {
+      static constant t(constant::True);
+      return &t;
+    }
+  }
+}