removed src for 2.9

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diff --git a/src/GF/Data/BacktrackM.hs b/src/GF/Data/BacktrackM.hs
deleted file mode 100644
index 790d11a83..000000000
--- a/src/GF/Data/BacktrackM.hs
+++ /dev/null
@@ -1,93 +0,0 @@
-----------------------------------------------------------------------
--- |
--- Module      : BacktrackM
--- Maintainer  : PL
--- Stability   : (stable)
--- Portability : (portable)
---
--- > CVS $Date: 2005/04/21 16:22:00 $
--- > CVS $Author: bringert $
--- > CVS $Revision: 1.4 $
---
--- Backtracking state monad, with r\/o environment
------------------------------------------------------------------------------
-
-{-# OPTIONS_GHC -fglasgow-exts #-}
-module GF.Data.BacktrackM ( -- * the backtracking state monad
-		    BacktrackM,
-		    -- * controlling the monad
-		    failure,
-		    (|||),
-		    -- * handling the state & environment
-		    readState,
-		    writeState,
-		    -- * monad specific utilities
-		    member,
-		    -- * running the monad
-		    foldBM,          runBM,
-		    foldSolutions,   solutions,
-		    foldFinalStates, finalStates
-		  ) where
-
-import Data.List
-import Control.Monad
-
-----------------------------------------------------------------------
--- Combining endomorphisms and continuations
--- a la Ralf Hinze
-
--- BacktrackM = state monad transformer over the backtracking monad
-
-newtype BacktrackM s a = BM (forall b . (a -> s -> b -> b) -> s -> b -> b)
-
--- * running the monad
-
-runBM :: BacktrackM s a -> s -> [(s,a)]
-runBM (BM m) s = m (\x s xs -> (s,x) : xs) s []
-
-foldBM :: (a -> s -> b -> b) -> b -> BacktrackM s a -> s -> b
-foldBM f b (BM m) s = m f s b
-
-foldSolutions   :: (a -> b -> b) -> b -> BacktrackM s a -> s -> b
-foldSolutions f b (BM m) s = m (\x s b -> f x b) s b
-
-solutions   :: BacktrackM s a  -> s -> [a]
-solutions = foldSolutions (:) []
-
-foldFinalStates :: (s -> b -> b) -> b -> BacktrackM s () -> s -> b
-foldFinalStates f b (BM m) s = m (\x s b -> f s b) s b
-
-finalStates :: BacktrackM s () -> s -> [s]
-finalStates bm = map fst . runBM bm
-
-
--- * handling the state & environment
-
-readState :: BacktrackM s s
-readState    = BM (\c s b -> c s s b)
-
-writeState :: s -> BacktrackM s ()
-writeState s = BM (\c _ b -> c () s b)
-
-instance Monad (BacktrackM s) where
-    return a   = BM (\c s b -> c a s b)
-    BM m >>= k = BM (\c s b -> m (\a s b -> unBM (k a) c s b) s b)
-	where unBM (BM m) = m
-    fail _ = failure
-
--- * controlling the monad
-
-failure :: BacktrackM s a
-failure = BM (\c s b -> b)
-
-(|||) :: BacktrackM s a -> BacktrackM s a -> BacktrackM s a
-(BM f) ||| (BM g) = BM (\c s b -> g c s $! f c s b)
-
-instance MonadPlus (BacktrackM s) where
-    mzero = failure
-    mplus = (|||)
-
--- * specific functions on the backtracking monad
-
-member :: [a] -> BacktrackM s a
-member xs = BM (\c s b -> foldl' (\b x -> c x s b) b xs)