b18: analysis percentage

The background analysis is greatly improved now that it is actually running in the background.

What is confusing, though, is that after closing Rando and reopening it, the progress always starts at 0%. It’s not clear whether it continues where it left off (as it should) and the percentage reflects the new progress, or whether the whole analysis starts over again (as one might think when seeing the zero). It would be helpful if progress picked up from the last percentage.

The same for when the analysis it turned off and back on.

Currently, the progress remains at 0% when toggling this setting, but CPU usage indicates the analysis is running.