macroprocessor: allow inline comments. closes #1550

preprocessor/macro/MacroFlex.ll

 /*
- * Copyright (C) 2008-2017 Dynare Team
+ * Copyright (C) 2008-2018 Dynare Team
  *
  * This file is part of Dynare.
  *
@@ -71,6 +71,8 @@ CONT \\\\
   yylloc->step();
 %}
 
+<STMT,EXPR,FOR_BODY,THEN_BODY,ELSE_BODY>["/"]["/"].*
+
 <INITIAL>^{SPC}*@#{SPC}*includepath{SPC}+\"([^\"\r\n:;|<>]*){1}(:[^\"\r\n:;|<>]*)*\"{SPC}*{EOL} {
                               yylloc->lines(1);
                               yylloc->step();