Tidy up/deprecate some FrameContainer getters.

FrameContainer shouldn't be responsible for exposing a WindowManager,
and shouldn't keep an IconManager reference just to pass it on to
other classes.

Change-Id: Id672fec154a19c999b078b3980681937f62bfb41
Reviewed-on: http://gerrit.dmdirc.com/2840
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Update submodules: plugins (new commits)

plugins:
    a831641 Chris Smith <chris@dmdirc.com>
            Fix most getIconManager() calls.

            Depends-On: Id672fec154a19c999b078b3980681937f62bfb41
            Gerrit: http://gerrit.dmdirc.com/2841

Change-Id: I1401800b36851502253bdbd6a8e68591d3e15220