Meta issue: fix gaps in code coverage

I'm in the process of marking a lot of the TestingParty08 issues down from critical bug to normal task, since a lot of coverage got added and we have no idea currently what is and isn't tested.

Since we need at least one release blocker dealing with test coverage, I'm opening this meta issue to track overall status and link off to test-only issues - which will hopefuly make our critical issues / pending bugs queues a bit more reflective of reality.

The first step here, would be for someone to run an updated code coverage report on core, I think R.Muilwijk did the most recent ones a month or so ago.