Scope? (add hPut, hPutStrLn, putStrLn for OsString)

Hi! would this library be a good fit for this functions?

```haskell
hPut :: Handle -> OsString -> IO ()
hPutStr :: Handle -> OsString -> IO ()
hPutStrLn :: Handle -> OsString -> IO ()
putStr :: OsString -> IO ()
putStrLn :: OsString -> IO ()
```

Here's (https://github.com/0rphee/os-string-io) a POC implementation (based on ).

Also, I guess he `-Ln` versions should be behind a `*.Word8` module like in bytestring, or under a similar scheme.