ETA for downloads (single and all) to complete

The app knows how large a download is, and how fast it's downloading. It would be very helpful to see an estimated time for how long is left of the download.

It would also be helpful, maybe even more so, if there in the footer of the application, where it's currently showing "n in progress * x MB/s" if it there also showed an ETA for _all_ the downloads to complete. Since it's already showing the total download speed, it shouldn't be too difficult to sum up all the incomplete download sizes and calculate a total estimate.