BREAKING CHANGE closes #873 - errors inside observers are not caught

> Do we know JSDOM would be any better?

I don't have any real experience with it, certainly not for this sort of thing - my only evidence is [this Twitter conversation](https://twitter.com/mhuusko5/status/483673020527955970). It stands to reason that JSDOM should be *much* faster than Phantom, and it would certainly sidestep some of the Phantom bugs we've encountered (no `Function.prototype.bind`, broken `Array.prototype.sort`, broken `Object.defineProperty` and so on) - but the big question is how accurately it mimics the DOM when it comes to things like event handling. I reckon it's worth investigating, though it's certainly not a huge priority. Node/browser isomorphism is just the icing on the cake.

Auto-creating the test pages has made life way easier, yeah - aside from the Phantom dependency, my only real gripe with QUnit is async, which Mocha does in a much nicer way IMHO.