Untie from Jest

[calebeby]

It would be nice to be able to use Test Mule with other test runners, like Ava or Mocha. Test Mule is slightly tied to Jest, and very tied to Jest's expect. We should test to see if Test Mule can be used in other test runners by loading Jest's expect into the other runners, and/or look into untying Test Mule from expect.

[gerardo-rodriguez]

Good call. 👍

For now, this feels like a lower priority unless someone can make a strong case for it. 😉