ListenerList is now perfectly, magically thread safe
There's no longer any need to synchronise when adding or
iterating to a listener list.
Change-Id: Ie39fbd92650bebffb13524e6054b187c3699833e
Reviewed-on: http://gerrit.dmdirc.com/1124
Reviewed-by: Gregory Holmes <greg@dmdirc.com>
Automatic-Compile: Chris Smith <chris@dmdirc.com>