deal with mtl/monads-tf conflict

I had been using -ignore-package monads-tf to deal with this, but
the XMPP library uses monads-tf, so that also ignores it. Instead,
use PackageImports to force use of mtl in my own code.

Command/Status.hs

@@ -5,11 +5,11 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE PackageImports, BangPatterns #-}
 
 module Command.Status where
 
-import Control.Monad.State.Strict
+import "mtl" Control.Monad.State.Strict
 import qualified Data.Map as M
 import Text.JSON
 import Data.Tuple