R1:6c049d06ce4d

Conpherence - change message rendering logic to eradicate possibility of duplicates

Summary:
Fixes T6713. Before this diff, we would update the DOM when various requests came back, but the logic to erase race conditions proved too tricky for me to get right. Instead, change the algorithm up and keep a set of transaction ids around per thread. When its time to update the transactions, sort the list of ids and just render the whole darn set again.

To make this work, this ends up adding transacton ids to…