GamePackage links open in a new tab

After I'm done playing a game, I habitually close the window, expecting to come back to the bgj site. Instead, I end up closing the window which had bgj in its history. This pull request opens game package links in a new tab, so that the expected behavior occurs.

This small patch spares me a lot of trouble if it gets accepted, and I hope it will help others as well - I do not think I am the only one who browses like this.