Add support for devices

Address code comments from previous commit

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

fs/copy_windows.go

@@ -25,3 +25,7 @@ func copyFileContent(dst, src *os.File) error {
 func copyXAttrs(dst, src string) error {
 	return nil
 }
+
+func copyDevice(dst string, fi os.FileInfo) error {
+	return errors.New("device copy not supported")
+}