@sueloverso, I've been meaning to futz a little with async operations (I've never written anything that used the API, and I wanted to take it out for a spin). Anyway, I changed test/format to do async operations along with cursor operations, and this branch has a couple of minor changes I made along the way, for your consideration.

@michaelcahill, I don't plan to push the actual changes to format to support asynchronous threads. If you see value in testing asynchronous operations in format, and you want those changes to live on, let me know.