convert git-annex branch access to ByteStrings and Builders

Most of the individual logs are not converted yet, only presense logs
have an efficient ByteString Builder implemented so far. The rest
convert to and from String.

Logs/Trust/Basic.hs

@@ -24,13 +24,13 @@ trustSet :: UUID -> TrustLevel -> Annex ()
 trustSet uuid@(UUID _) level = do
 	c <- liftIO currentVectorClock
 	Annex.Branch.change trustLog $
-		showLog showTrustLog .
+		encodeBL . showLog showTrustLog .
 			changeLog c uuid level .
-				parseLog (Just . parseTrustLog)
+				parseLog (Just . parseTrustLog) . decodeBL
 	Annex.changeState $ \s -> s { Annex.trustmap = Nothing }
 trustSet NoUUID _ = error "unknown UUID; cannot modify"
 
 {- Does not include forcetrust or git config values, just those from the
  - log file. -}
 trustMapRaw :: Annex TrustMap
-trustMapRaw = calcTrustMap <$> Annex.Branch.get trustLog
+trustMapRaw = calcTrustMap . decodeBL <$> Annex.Branch.get trustLog