R1:78bfcc32217a

Conpherence - change "A, B, C..." subtitle to "A: what most recent person said" when we can

Summary:
For the price of loading transactions more consistently, we get a better subtitle. We do this in all cases EXCEPT for when we're grabbing handles, because that makes the handles pretty heavy weight and I could even feel the perf hit on my development machine and we don't use subtitle there anyway. We may want to cache the latest message on the conpherence thread object to improve performance here as well…