Run tests with latest steal@1.x

[m-mujica]

Closes #70

• Upgrade tests to fix a silent rejection thrown by testee, it seems to dislike the way QUnit was set up. We are no longer using asyncTest, or QUnit.start/stop. Instead we are using the assert.async() API

• Upgrade testee to get the latests bug fixes

Instead of

the output now looks like:

In the browser I cannot get the tests to fail, but for some reason through testee sometimes some of the tests just hang... Pushing the PR to take a look at the CI output.

[m-mujica]

ok, this is good to go now I think.

[matthewp]