remove SwapFocus (which is no longer possible)

This module depended on the focus stack.

SwapFocus.hs

@@ -1,30 +0,0 @@
-module XMonadContrib.SwapFocus ( swapFocus ) where
-
--- swaps focus with last-focussed window.
-
--- To use:
--- import XMonadContrib.SwapFocus ( swapFocus )
-
---    , ((modMask .|. shiftMask, xK_Tab), swapFocus)
-
-import Control.Monad.State
-
-import Operations ( refresh )
-import XMonad ( X, WindowSet, windowset )
-import StackSet ( StackSet, peekStack, popFocus, pushFocus, current )
-
-sf :: (Integral i, Integral j, Ord a) => StackSet i j a -> Maybe (StackSet i j a)
-sf w = do let i = current w
-          f1 <- peekStack i w
-          f2 <- peekStack i $ popFocus i f1 w
-          return $ pushFocus i f2 $ pushFocus i f1 w
-
-swapFocus :: X ()
-swapFocus = smartwindows sf
-
--- | smartwindows. Modify the current window list with a pure function, and only refresh if necesary
-smartwindows :: (WindowSet -> Maybe WindowSet) -> X ()
-smartwindows f = do w <- gets windowset
-                    case (f w) of Just f' -> do modify $ \s -> s { windowset = f' }
-                                                refresh
-                                  Nothing -> return ()