[illumos-Developer] clean up stale libplot and friends (lib300, etc.)

[Garrett D'Amore]

This is covered in bug 364: https://www.illumos.org/issues/364

This EOF would *potentially* break some applications, but I am unaware
of any applications which use any of these libraries.  Carrying this
bitrotten code around just for the "sake" of binary compatibility
without any known consumers of it, seems ridiculous to me.   Technically
this would have been harder to remove under PSARC rules at Sun, but I
think we can do better here.

Can anyone think of *any* reason we should keep these libraries around?

Note that source compatibility is achievable (or very nearly so) with
the much more modern GNU plotutils library, which distros can supply if
they need this for certain applications.

Applications that really need these ancient libraries probably are in
serious need of updating....  staleware.

If anyone has any serious objections to this, please place them in the
bug description or report them here.

	- Garrett