doesn't seem to pass a last two tests:
Rejects submission of event before address is deleted: UNTESTED (blocked: not replacing newer parameterized replaceable event)
Accepts submission of event after address is deleted: FAIL (blocked: not replacing newer parameterized replaceable event)
but this may be because it tombstones deleted events and is rejecting resubmission of an older version that was thus deleted, so i'm calling it done
also changes the interface of unmarshal to not return an error, which is something that should really belong elsewhere, both a thing to forget and a thing to have divergences in, not the right way to do it
