Restore uncompressed xcf file from tmp if GIMP crashed during .xcf.* compression
When GIMP crashes during compression of a large image, the uncompressed file will still be available in the "tmp" folder. However, currently, GIMP restores a possibly corrupted backup (e.g. made during a multi-step operation) instead and does not inform the user about the availability of an uncorrupted backup file.
Automatically determine if any of the .xcf files in the "tmp" folder has a newer modification date than the normal backup. If this is the case, use (or at least offer to use!) the latest .xcf file from the "tmp" folder instead.
Offer the user to use the latest .xcf file from the "tmp" folder instead.