Improve tracking and publication of ReflectiveCallable objects

This release fixes a fundamental deficiency with my initial attempt to record and publish ReflectiveCallable objects. Saving these in the AtomIdentity object and publishing from there wouldn't have worked for atomic tests with configuration methods. I now record every "callable" object with its associated JUnit framework object.
I also fixed the handling of ignored tests, generating an AtomicTest object to send with the notification.

NOTE: This is a breaking change, and I should probably advance to the next major version, but the feature I broke is so obscure that I marked it as a feature release instead.