mount in iframe

[dereke]

I think we should consider (and try) loading each test into a new iframe - the reason being that when the app fiddles around with the URL you can't just refresh to run the test again. It would also help to ensure the app is always run in a clean state i.e. no event handlers hanging around.
We could also (possibly) run more than one test at a time??
I think this can easily be implemented inside the mount component