Releases for Registry

Initial Drupal 7 port

Summary
This fix adds a number of improvements to the way values are handled, locked and returned from the registry, as well as adding default information for the request, current user, and loaded node on node view pages.

Main changes

Callback entries
Entries can now be set using a callback instead of a fixed value. This ensures that the current value of the item is always loaded. The API function registry_set_callback() can be used to do this.