Indicate labeling round progress and/or retraining status

While labeling alone or with a crowd, add to the labeling UI an indication of how much of a "round" has been completed, and whether/when retraining has been initiated. For example, with the current settings (5 samples per labeling round; 100 samples to label before retraining) I must return to the landing page to determine how many samples remain to be labeled before retraining is initiated. It would be helpful if some sort of "group" or "round" progress bar could indicate this, possibly next to existing 1/5->5/5 indication of my progress during the current labeling task (5 candidates). Similarly, when the model starts retraining, perhaps it is worth notifying the current labeler(s) -- unless their crowd-sourced efforts are stored and will eventually trigger and be used in a next retraining event... otherwise, the user worries that their extra effort (beyond 100 samples in this example) may have been wasted.