Fixed ClasssyPrelude version to 0.9.0 and fixed things for it.

ihaskell.cabal

@@ -59,7 +59,7 @@ library
                        base64-bytestring    >=1.0,
                        bytestring           >=0.10,
                        cereal               >=0.3,
-                       classy-prelude       >=0.7,
+                       classy-prelude       ==0.9.0,
                        cmdargs              >=0.10,
                        containers           >=0.5,
                        directory            -any,
@@ -129,7 +129,7 @@ executable IHaskell
                        aeson                >=0.6 && < 0.8,
                        bytestring           >=0.10,
                        cereal               >=0.3,
-                       classy-prelude       >=0.7,
+                       classy-prelude       ==0.9.0,
                        containers           >=0.5,
                        directory            -any,
                        ghc                  ==7.6.*,
@@ -151,7 +151,7 @@ Test-Suite hspec
                        base64-bytestring    >=1.0,
                        bytestring           >=0.10,
                        cereal               >=0.3,
-                       classy-prelude       >=0.7,
+                       classy-prelude       ==0.9.0,
                        cmdargs              >=0.10,
                        containers           >=0.5,
                        directory            -any,

src/IHaskell/Display.hs

@@ -24,7 +24,6 @@ import qualified Data.ByteString.Char8 as Char
 import Data.Aeson (Value)
 
 import Control.Concurrent.STM.TChan
-import Control.Monad.STM
 import System.IO.Unsafe (unsafePerformIO)
 
 import IHaskell.Types