ListenerList is now perfectly, magically thread safe
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 <79e2475f81a6317276bf7cbb3958b20d289b78df@dmdirc.com>
Automatic-Compile: Chris Smith <711c73f64afdce07b7e38039a96d2224209e9a6c@dmdirc.com>

DMDirc/Util