Added a new default_layout parameter to get rid of the hard-coded sloan layouts used when a new page is added. Default value is the old hard-wired one, but now our standard install.xml can set it to zen, and when someone has time site theme switching can change it, too.
Get rid of the get_page_header_stuff kludge. Add a proc to set the portal page CSS for the current layout (using template::head API), to be called from layout templates