add a hide button, improve error message, fadeIn and out
Merge branch '20130809-global-errors' of github.com:scraperwiki/custard into 20130809-global-errors
error bar shows and hides properly

* We're no longer removing all alerts on routes <-- WARNING
* Make sure fullscreen doesn't overlap toolbar when we show alert
* Make alert flash
replace console.warns with error events

Also don't raise error events for some stuff we already handle with
alerts