Prune 27 obsolete ports

FreeBSD Ports maintainers have already deleted the following:
  devel/gconfmm
  devel/libXGP
  devel/libYGP
  devel/libglademm
  devel/lua50-app
  devel/lua50-compat51
  devel/lua50-filename
  devel/lua50-gettext
  devel/lua50-posix
  devel/lua50-pty
  devel/valide
  graphics/libgnomecanvasmm
  japanese/mobileimap
  lang/lua50
  lang/objc
  lang/tolua++50
  lang/tolua50
  multimedia/tovid
  net/lua50-luasocket
  palm/synce-trayicon
  security/dissembler
  security/linux-pam-docs
  security/squidclamav
  sysutils/dircomp
  textproc/p5-Lucene
  x11-toolkits/libgnomeuimm
  x11/libgnomemm