This change means that the connection isn't swapped from new context to
old, which makes dealing with websockets lots easier. It does require
that clients storing a list of their subscriptons.

When using -v and the broker receives a SIGHUP, verbose logging was being disabled. This has been fixed.

This is due to the complexity of checking wildcard ACLs against wildcard
subscriptions. This does not have a negative impact on security because
checks are still made before a message is sent to a client.  Fixes bug

Thanks to Jan-Piet Mens and Christoph Krey.