debugging improvements

add timestamps to debug messages

Add lots of debug output in the assistant's threads.

Option.hs

@@ -17,6 +17,9 @@ module Option (
 
 import System.Console.GetOpt
 import System.Log.Logger
+import System.Log.Formatter
+import System.Log.Handler (setFormatter, LogHandler)
+import System.Log.Handler.Simple
 
 import Common.Annex
 import qualified Annex
@@ -48,8 +51,13 @@ common =
 		setfast v = Annex.changeState $ \s -> s { Annex.fast = v }
 		setauto v = Annex.changeState $ \s -> s { Annex.auto = v }
 		setforcebackend v = Annex.changeState $ \s -> s { Annex.forcebackend = Just v }
-		setdebug = liftIO $ updateGlobalLogger rootLoggerName $
-			setLevel DEBUG
+		setdebug = liftIO $ do
+			s <- simpledebug
+			updateGlobalLogger rootLoggerName
+				(setLevel DEBUG . setHandlers [s])
+		simpledebug = setFormatter
+			<$> streamHandler stderr DEBUG
+			<*> pure (simpleLogFormatter "[$time] $msg")
 
 matcher :: [Option]
 matcher =