Removed the ping/ thing - that was just a bandwidth waster. Added some
application cache monitoring code. Among other things, it auto-reloads
the page when the appcache is updated with new code.
We now periodically check the application cache. We do it often if
running offline, but rarely, (once every 10 minutes) if running online.
Ooops - NOW we do it rarely if running offline. I was doing it every 10
seconds for testing...