Merged oacs-5-6 to HEAD. HEAD now installs and passes all core tests. There may still be some lingering problems due to my screwing up the oacs-5-6 branch earlier, I'll be looking into this later.
1. First shot at sitewide admin ui for global parameters. You can edit them from the sitewide admin page list that was previously built for packages that have a sitewide-admin subdirectory. Package is now displayed for either the existence of sitewide-admin or global parameters.
2. Did something I'd wanted to do for some time. When Nima added the parameter_changed callback in acs subsite, he actually *moved* the set_value call there. I've changed it so it more rationally sets the value in the parameters page, then calls the parameter_changed callback.
3. Invented a global_parameter_changed callback that works as the regular parameter_changed callback. This was necessary to avoid breaking existing uses of parameter_changed.
More testing is required before release (which will hopefully happen tomorrow, Sunday Apr 4).