feat: Autoupdate.check returns true/false depending on whether it is supported
fix: disabling or setting autoupdate interval via data-autoupdate on <html>
feat: trigger appCache events

* noupdate
* cached
* updateready
* progress
* downloading
fix: no updateready event on initial caching
docs(README): iframe hack
feat: added iframe hack

Thanks to the Financial Times Labs Team! Find out more at
http://labs.ft.com/category/tutorial/
feat: AutoUpdate is now appCacheNanny!