Added support for HttpOnly cookies. 

Great project.  I thought I would lend a hand by adding support for HttpOnly cookies.  

Thanks so much!

References 
* https://www.owasp.org/index.php/HttpOnly
* http://www.codinghorror.com/blog/2008/08/protecting-your-cookies-httponly.html
* http://en.wikipedia.org/wiki/HTTP_cookie#HttpOnly_cookie