pkgsrc name collisions

[Taylor R Campbell <campbell+netbsd-tech-pkg%mumble.net@localhost>]

The following packages have colliding names in different categories:

{fonts,sysutils}/gnome-font-viewer
{games,www}/hugo
{mbone,misc}/mdp
{textproc,x11}/xp

gnome-font-viewer and mdp are PKGBASE collisions.  The two
gnome-font-viewers appear to be the same software (imported and then
updated at different times), but in the case of mdp, this means
pkg_add or pkgin will try to install the wrong package for `mdp' if
you want misc/mdp because mbone/mdp has a higher version number.

www/hugo sets PKGNAME=go-hugo-... so its PKGBASE doesn't collide with
games/hugo.  textproc/xp sets PKGNAME=XP-... (uppercase) so it doesn't
collide with x11/xp with PKGNAME=xp-... (lowercase).  But it appears
to be essentially accidental that these don't collide.

I think we should:

1. Delete fonts/gnome-font-viewer -- sysutils/gnome-font-viewer is
   more up-to-date, so there's no sense in keeping both; if we want
   both versions the PKGBASE or at least directory name should be
   versioned.

2. Delete mbone/mdp -- not clear if it's alive or relevant today (or
   if any of mbone/ is), but the package description hasn't been
   touched since 2002 except for largely automated infrastructure
   changes, and the web site seems to be gone.  (cc'ing manu@, who
   imported it.)

3. Maybe rename www/hugo to www/go-hugo to match its PKGBASE.  It's
   not strictly a problem for the directory name to collide when the
   PKGBASE does not, but it's confusing.  Or, maybe delete games/hugo;
   web site has been gone since 2008, unclear if there's anything
   culturally significant in the interactive fiction format it
   interprets.

4. Delete textproc/xp (and textproc/xt).  It's a Java XML parser that
   hasn't been touched upstream since 1999, used in pkgsrc only by
   textproc/xt, a Java XSLT processor, not used by anything in pkgsrc.
   There's a standard Java API for XML parsing and XSLT processing
   anyway.

Open to other suggestions, including `skip (3) and (4), collision in
the directory name alone isn't that big a deal'.  Opinions?