Make on-the-fly ranking statistic assignment logic more clear
Currently, the StreamThinca class will only assign ranking statistic values if "cluster" is set to true. Long term I think we need to figure out a way to assign lrs to all of the candidates in the online running mode, not just the highest snr candidate. But until then, there should at least be comments explaining that this is the behavior. You can see in  that a dictionary is populated if cluster is set to True, and then the objects contained in that dictionary are assigned ranking statistics a few lines down.