- Add a note on how to upgrade to GNOME 2.16

GNOME has been updated to 2.16 and all GNOME components have been
moved from X11BASE to LOCALBASE, to upgrade your GNOME desktop and
applications you will need either sysutils/portupgrade or
sysutils/portmanager.

Portupgrade users:
pkgdb -Ff
portupgrade -rf glib-2\* cairo gnome-doc-utils gnome-mime-data \
gnome-audio startup-notification dbus

Portmaster users:
portmaster -r pkg-config\*

Approved by:portmgr (marcus)