Cleaner approach to getting exception in onerror
Fix loading on IE6/7

You can't set properties on window.setTimeout (nor call
window.setTimeout.call)
Add current dom node to event
Remove now-absent concat task
Tidy up and polish

Works fully in IE 10/11, Firefox/Safari/Opera/Chrome.

In IE 6/7/8: Can get fake bracktraces (arguments.callee.caller). Can't get events.
In IE 9: Can't get backtraces (fake or not). Can get events.
In Firefox 3.5: Can't get events or stack-traces automatically.
fix test runner
Add a smoke test