RFE: More and better cache handling options

[contyk]

The default -c option is nice but as the manpage suggests, one should also remove the now empty directories. It would be nice if directory cleanup were part of the -c action, saving inodes and such.

Additionally I would like to suggest -C option that does the opposite. Takes the path arguments, creates their thumbnails, and exits. So that the user doesn't have to wait for thumbnails to be generated the first time they open the files.

Both of these would make for a nice cronjob. Build, clean. Or the other way around. Even better if they can be combined. I imagine something like fd -tf '\.(gif|jpe?g|png)$' ~ | sxiv -c -C -.