Shared directories can now be created independently by the pacakges
needing them and will be removed automatically by pkg_delete when empty.
Packages needing empty directories can use the @pkgdir command in PLIST.
Discussed and ok'd in thread starting at
http://mail-index.netbsd.org/tech-pkg/2009/06/30/msg003546.html
actions on every page or on the current page. Specifically, actions
are performed after the page is composed, but before it is shipped,
so they can be used to prepare the output page in tasks like putting
watermarks in the background, setting the next page layout, etc.