Cleanup procs

Maintain a flatfile containing the process identifiers of all active activity servers. Ensure that any "zombie" processes are killed whenever starting the top-level server. (This solution originally described in gh-118.)

@mzgoddard Mind taking a look at this?
`.then` chain done with `.then(done, done)`. That way any errors in read or your asserts propagate to the test runner. Currently errors in `read` or in these asserts will result in timeouts without possible helpful error messages for the tests.