use filepath-bytestring for annex object manipulations

git-annex find is now RawFilePath end to end, no string conversions.
So is git-annex get when it does not need to get anything.
So this is a major milestone on optimisation.

Benchmarks indicate around 30% speedup in both commands.

Probably many other performance improvements. All or nearly all places
where a file is statted use RawFilePath now.

Utility/InodeCache.hs

@@ -22,7 +22,6 @@ module Utility.InodeCache (
 	readInodeCache,
 	showInodeCache,
 	genInodeCache,
-	genInodeCache',
 	toInodeCache,
 	likeInodeCacheWeak,
 
@@ -182,12 +181,8 @@ readInodeCache s = case words s of
 		return $ InodeCache $ InodeCachePrim i sz (MTimeHighRes t)
 	_ -> Nothing
 
-genInodeCache :: FilePath -> TSDelta -> IO (Maybe InodeCache)
+genInodeCache :: RawFilePath -> TSDelta -> IO (Maybe InodeCache)
 genInodeCache f delta = catchDefaultIO Nothing $
-	toInodeCache delta f =<< getFileStatus f
-
-genInodeCache' :: RawFilePath -> TSDelta -> IO (Maybe InodeCache)
-genInodeCache' f delta = catchDefaultIO Nothing $
 	toInodeCache delta (fromRawFilePath f) =<< R.getFileStatus f
 
 toInodeCache :: TSDelta -> FilePath -> FileStatus -> IO (Maybe InodeCache)
@@ -208,8 +203,8 @@ toInodeCache (TSDelta getdelta) f s
  - Its InodeCache at the time of its creation is written to the cache file,
  - so changes can later be detected. -}
 data SentinalFile = SentinalFile
-	{ sentinalFile :: FilePath
-	, sentinalCacheFile :: FilePath
+	{ sentinalFile :: RawFilePath
+	, sentinalCacheFile :: RawFilePath
 	}
 	deriving (Show)
 
@@ -226,8 +221,8 @@ noTSDelta = TSDelta (pure 0)
 
 writeSentinalFile :: SentinalFile -> IO ()
 writeSentinalFile s = do
-	writeFile (sentinalFile s) ""
-	maybe noop (writeFile (sentinalCacheFile s) . showInodeCache)
+	writeFile (fromRawFilePath (sentinalFile s)) ""
+	maybe noop (writeFile (fromRawFilePath (sentinalCacheFile s)) . showInodeCache)
 		=<< genInodeCache (sentinalFile s) noTSDelta
 
 data SentinalStatus = SentinalStatus
@@ -256,7 +251,7 @@ checkSentinalFile s = do
 				Just new -> return $ calc old new
   where
 	loadoldcache = catchDefaultIO Nothing $
-		readInodeCache <$> readFile (sentinalCacheFile s)
+		readInodeCache <$> readFile (fromRawFilePath (sentinalCacheFile s))
 	gennewcache = genInodeCache (sentinalFile s) noTSDelta
 	calc (InodeCache (InodeCachePrim oldinode oldsize oldmtime)) (InodeCache (InodeCachePrim newinode newsize newmtime)) =
 		SentinalStatus (not unchanged) tsdelta
@@ -281,7 +276,7 @@ checkSentinalFile s = do
 	dummy = SentinalStatus True noTSDelta
 
 sentinalFileExists :: SentinalFile -> IO Bool
-sentinalFileExists s = allM doesFileExist [sentinalCacheFile s, sentinalFile s]
+sentinalFileExists s = allM R.doesPathExist [sentinalCacheFile s, sentinalFile s]
 
 instance Arbitrary InodeCache where
 	arbitrary =