upgrade to awsbox 0.6.x for much better performance and happy new features

There's been a flurry of improvements to awsbox.  You might consider upgrading - the most interesting change is a migration to nginx (which preserves WebSocket support if you choose to use that for more efficient presence), and runs circles around the old http_proxy thing.  Also, this includes multi-region support so you can explore how we create a multi-region deployment...

Here's a full list of improvments: 
https://github.com/mozilla/awsbox/blob/v0.6.2/ChangeLog#L1-L48