Some admin page security improvements.
fixes the 404ing that was happening when you tried to load the /img/loader.gif on a domain that ended in /page/blah.
increases efficiency of new cacheing of front pages by caching all  pages below the page last loaded + 50 extra pages into the future.

Also allows for easy adjustment of the number of minutes between cacheing
whoops, forgot to set the fetch back to 30 from 3
simplified the page_time_list_tuple to return section, no longer needs the else clause long after the update. Simply renames the variable after the for loop just before returning it.
fixes an error where if you add a page beyond current content, it would 500. Now, however, if the page is beyond the list of content, it will simply load the last page of content… that is the page that says "end of content"