fix focus issue for XMonad.Actions.Warp.banishScreen
fix focus issue for XMonad.Actions.Warp.banishScreen


This patch ensures that the focus (or in fact the whose windowset)
does not change as a result of a banishScreen.  The way this is implemented
will become problematic if xmonad ever goes multithreaded.

0/xmonad-contrib,mathstuf/xmonad-contrib,mathstuf/xmonad-contrib,CaptainPatate/xmonad-contrib,CaptainPatate/xmonad-contrib,ohlus/xmonad-contrib,ohlus/xmonad-contrib,mathstuf/xmonad-contrib,f1u77y/xmonad-contrib,f1u77y/xmonad-contrib,CaptainPatate/xmonad-contrib,0/xmonad-contrib,ohlus/xmonad-contrib,0/xmonad-contrib,xmonad/xmonad-contrib,pjones/xmonad-test,xmonad/xmonad-contrib