leave date marker dotfiles in directories
change option to -T. remove cruft. fix pylint stuff. rename record_date() to record_timestamp()
move pool joining to directory handling section so timestamp recording always happens after files in subdirs are optimized
clean up record_timestamp exclusion logic. trap io error on timestamp write. clean up path join. exclude timestamp from optimization attempt
revert back to only repooling for recompressed comics. Don't drop timestamps all over the filesystem, instead crawl up the dirtree
add todo
don't list files we're not trying with
remove old timestamps because lookup obsoletes them