Thanks to JP Mens.

Conflicts:
	ChangeLog.txt

Fix subscriptions being deleted when clients subscribed to a topic
beginning with a $ but that is not $SYS.

Thanks to David Woodward.

Crash may occur for ACLs that do not include a %u and clients that
connect without a username.

Thanks to Karl Palsson.

Thanks to Tobias Assarsson.

Thanks to Stefan Borsje.