prune script: LOOK returned wrong results, use grep
Prune 13 obsolete ports

FreeBSD Ports maintainers have already deleted the following:
  audio/icecast
  databases/akonadi-google
  devel/py-setuptools
  japanese/jisx0213-fonts
  mail/gmime
  math/eigen
  net-mgmt/argus
  net/freeradius
  ports-mgmt/portcheck
  www/igal
  x11-fonts/gentium
  x11-toolkits/gtkglarea
  x11/oooqs