RFC: bsdtar in 5.3

[Tim Kientzle]

I would like to make bsdtar the default
FreeBSD system tar for -CURRENT within
the next week or so.

That should give it broad enough usage
over the next couple of months to prove
that it's ready for 5-STABLE.

My plan:

   * Make /usr/bin/tar default to a symlink
     to /usr/bin/bsdtar as soon as possible.
     (Currently, it defaults to /usr/bin/gtar
     unless you build WITH_BSDTAR.)

   * Leave /usr/bin/gtar in the base system
     through the 5.x cycle.

   * For 6.0, remove /usr/bin/gtar and rename
     /usr/bin/bsdtar to /usr/bin/tar.

Any objections, suggestions, or comments?

Tim Kientzle