Changes to client.c support the need for directories to be processed by whatever

Changes to client.c support the need for directories to be processed by whatever
action is passed to do_dir.

Changes to clitar.c as requested by Canon Information Systems Research Australia:

1. Support restoring long file names
2. Write directory entries to TAR files as first part of setting directory create
   times
3. Ensure zero length files get correct mtime
4. Allow DOS and UNIX pathnames in command line parameters.
(This used to be commit 0c228f0b33950c8d38de0529e88a38848742a50d)