Address papercuts

[mpobaschnig]

From GNOME Software review:

I would actually give it 4.5 stars, or 9/10. It gets the job done and I use it daily for creating backups of my data. It's just a little rough around the edges.

For example, if you delete a vault, there's no visual feedback when you press the "Remove" button. Because deleting a large vault can take a minute, you're stuck sitting there wondering if the mouse click didn't register, if the app froze, or if it's actually performing the delete operation.

Also -- and I'm fully aware this is not a normal use case -- I happened to lose power in the middle of a copy operation. From that time on, rsync would give me a "failed to stat files" message for a particular folder, and trying to remove the folder just resulted in "permission denied" errors. Finally had to delete and re-create the entire vault. So maybe a little improvement in error recovery would be useful.

So indeed, we should focus more on error handling on edge cases and address these paper cuts.