Removed support for ITabbedDisplayMgr from TOverviewFrame because it no longer has tabs. This means that the Ctrl+Tab and Shift+Ctrl+Tab key presses no longer change the grouping.
Added new SelectGrouping and SelectedGroupingIdx methods to IOverviewDisplayMgr and implemented these in TOverviewFrame.
Modified TMainDisplayMgr re the above changes no ensure that TOverviewFrame is no longer referenced via the ITabbedDisplayMgr interface.
