New autosave feature for meta boxes

Meta boxes now have an autosave feature, which is set to false by
default.  All you have to do is set `autosave` to an int value, which is
set as seconds 9 60 seconds = 1 min, 60 * 60 = hour).  First meta box in
main demo file now set to autosave every 60 seconds.
Fixed name issue with taxonomy