Introduce EConcatMarked "<>+>" as operator.

* src/ltlast/binop.cc, src/ltlast/binop.hh: Introduce
EConcatMarked ("<>+>").
* src/ltlvisit/basicreduce.cc, src/ltlvisit/consterm.cc,
src/ltlvisit/lunabbrev.cc, src/ltlvisit/nenoform.cc,
src/ltlvisit/reduce.cc, src/ltlvisit/simpfg.cc,
src/ltlvisit/syntimpl.cc, src/ltlvisit/tostring.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2tgba_lacim.cc, src/tgba/formula2bdd.cc,
src/tgba/formula2bdd.cc: Deal with it if possible or ignore
it.

src/ltlast/binop.cc

@@ -123,6 +123,8 @@ namespace spot
 	  return "M";
 	case EConcat:
 	  return "EConcat";
+	case EConcatMarked:
+	  return "EConcatMarked";
 	case UConcat:
 	  return "UConcat";
 	}
@@ -256,6 +258,7 @@ namespace spot
 	    }
 	  break;
 	case EConcat:
+	case EConcatMarked:
 	  //   - 0 <>-> Exp = 0
 	  //   - 1 <>-> Exp = Exp
 	  //   - #e <>-> Exp = 0

src/ltlast/binop.hh

@@ -55,6 +55,7 @@ namespace spot
 		  W, //< weak until
 		  M,  //< strong release (dual of weak until)
 		  EConcat, // Existential Concatenation
+		  EConcatMarked, // Existential Concatenation, Marked
 		  UConcat // Universal Concatenation
       };