fog/fog — pull request #685 by jkrall (2012-01-04 10:04:03+00:00)
Title: Fixed SQS :receive_message mock bug

There is a bug in the SQS mock... line 40:
```keys = queue[:messages].keys[0, max_number_of_messages]```

The problem is that this limits the messages that it iterates over to only the first N... but if all of those N messages turn out to be "invisible", then it returns []. Instead, it should return the first N _visible_ messages.

I reworked the logic to make that happen.