Have a look at this (related) previous discussion http://news.ycombinator.com/item?id=670453 http://news.ycombinator.com/item?id=670453 and especially this comm

Have a look at this (related) previous discussion http://news.ycombinator.com/item?id=670453 http://news.ycombinator.com/item?id=670453 and especially this comment http://news.ycombinator.com/item?id=670795 http://news.ycombinator.com/item?id=670795