Code review comment for lp:~feng-kylin/unity/MoveDashToBottom

Please revert the changes to PanelView, because some reasons:
 1) You should disconnect from form_factor changes (or expect crashes)
 2) The way is done right now will affect Hud as well
 3) After thinking again, I've the impression that it's better to keep the
    panel blurred, also when the dash is at the bottom, because it's a way
    to underline that panel is controlling the dash.

So, other than that (and the small change in OverlayRenderer and DashStyle if you want) I think we're ok to go.