table by hand anymore! Update the group_policies table and then run
the script to update the permissions table (sbin/update_permissions).

Details:

My original thought when I started this was that I would be able to
replace the existing nodetypeXpid_permissions table with this new
stuff. Well, it turns out that this was not a good thing to do, for a
couple of reasons:

  * Engineering: We access the nodetypeXpid_permissions table from three
    different languages, and no way I wanted to rewrite this library in
    in python and php!

  * Performance: We access the nodetypeXpid_permissions from the web
    interface, on every single page load. In fact, we access it twice if
    if you count the FreePCs() count that we put at the top of the menu.
    Going through this library on each page load would be a serious drag.

So, rather then actually get rid of the nodetypeXpid_permissions table, I
decided to keep it as a "cache" of permissio...