handle utf8 properly in error messages (issue #5)

Utils.hs

@@ -11,7 +11,8 @@ import Control.Monad.Error
 import Ledger
 import Options (Opt,ledgerFilePathFromOpts,optsToFilterSpec)
 import System.Directory (doesFileExist)
-import System.IO
+import System.IO (stderr)
+import System.IO.UTF8 (hPutStrLn)
 import System.Exit
 import System.Cmd (system)
 import System.Info (os)

tests/unicode-error-message.test

@@ -11,3 +11,4 @@ could not balance this transaction, amounts do not add up to zero:
     дебит              1
     кредит            -2
 
+