Last file processed

[soulky]

It can happen that ffmpeg or other codec crashes on thumbnailing process due to an incompatible ord wrongly encoded file. This causes xnviemp to crash but it is not a xnviemp issue.
For that it would be good to know which is the last file that has been touched.
A suggestion would be a toggle to switch the progress bar into a bar which always shows the currently processed filename. So when xnviemp crashes then the last file name is visible in that bar.