post-ignore call failure bugs

This is a WIP branch for <https://trello.com/c/lDWUlpNE/231-0-as-a-user-i-should-be-able-to-receive-a-call-when-i-ve-got-a-call-timed-out-dialog-for-that-user>.  

So far, it fixes the call model and tests to allow transitions from both pending and timeout, and adds one change to make the events and logs more comprehensible.

Unfortunately, the complete fix(es) isn't(aren't) as simple as Standard8 and I were expecting.  More in the Trello.