Implement new.target

lib/ast.js

@@ -1003,6 +1003,10 @@ var AST_Symbol = DEFNODE("Symbol", "scope name thedef", {
     $documentation: "Base class for all symbols",
 });
 
+var AST_NewTarget = DEFNODE("NewTarget", null, {
+    $documentation: "A reference to new.target"
+});
+
 var AST_SymbolAccessor = DEFNODE("SymbolAccessor", null, {
     $documentation: "The name of a property accessor (setter/getter function)"
 }, AST_Symbol);