Use events for title changes in MainFrame.

Change-Id: Ia8c6706f822f553de37fee9ccd4e21c564596b71
Reviewed-on: http://gerrit.dmdirc.com/3759
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Remove unused ctor param in MainFrame.

Change-Id: I0bafdeb68a0f8eab9f9d8fbc7ee059494042ee96
Reviewed-on: http://gerrit.dmdirc.com/3760
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager