Fixes issue 3438: topic history labels lose meta data

Change-Id: I1cc75e88252373ca7c7621806ef8f9a4f53bb6fd
Reviewed-on: http://gerrit.dmdirc.com/351
Reviewed-by: Chris Smith <chris@dmdirc.com>
Tested-by: Chris Smith <chris@dmdirc.com>

Change-Id: Id7fd280249c3cd5d72e5ba5020fb75f11c170169
Reviewed-on: http://gerrit.dmdirc.com/345
Reviewed-by: Chris Smith <chris@dmdirc.com>
Tested-by: Chris Smith <chris@dmdirc.com>

Change-Id: Ia8a8173f67a7d9f423407f82b2a3c776e87b077e
Reviewed-on: http://gerrit.dmdirc.com/323
Reviewed-by: Gregory Holmes <greboid@dmdirc.com>
Tested-by: Gregory Holmes <greboid@dmdirc.com>