adding max-age to validation

I don't know if it is officially part of the basic version cookie standard but PHPsends the max-age field when it sets a cookie to expire, this PHP

```
setcookie ("notsession", "I am", time()+60*60*24*30, "", "", true, true);
```

sets the following cookie:

```
Set-Cookie: notsession=I+am; expires=Thu, 13-Nov-2014 12:12:44 GMT; Max-Age=2592000; secure; httponly
```