Wait a limited time to reach a specific breakpoint.
Test failures: don't go interactive if not on a terminal.
New unit test: abort PREPARE, lose ticket.

Does fail in the current version.
Bugfix: lose ticket during PREPARE even if there are retries left.
Unit tests: broadcasted packets were seen multiple times, once for each site.
Losing the ticket has to happen in every state.
Incrementing the retry counter is done by ticket_activate_timeout().
Bugfix: time comparison was wrong way around.
After losing a ticket we need to do do other jobs as well.
Make "revoke" on a revoked ticket return success immediately.
When receiving an OP_COMMIT, say that it was received.
TODO comment added.
Losing a ticket shouldn't cancel an ongoing proposal.
Fix CATCHUP answer: only tell old news.
After CATCHUP we need to schedule for further work.

Perhaps we have to acquire the ticket, eg. if we're the earlier site to
come back, with an arbitrator alive.