QUnitjs 2.0 doesn't seem to support IE8. I asked for clarification here: qunitjs/qunit#1031
I'm merging this in immediately to unbreak the build but please someone review this when you get a chance.
revert back to qunitjs 1.x. Add es5-shim to tests
@gkatsev reverted back to qunitjs 1.x to unbreak IE8. Added es5-shim …
…to tests. closes #3533