Major fixes for Error Queue

Found some issues in the error handing of Consumers where:

• Consumers were republishing messages back to their own queue twice on error due to a flag being set incorrectly.
• Due to the some overzealous refactoring, error queues were not being created or published to.
• The loopback transport was not being set up properly.
• Synced up the version of Stact and Magnum