FIXME: use same signal handler (signal_handler) - should it use
special siginfo arguments or not (SA_SIGINFO)? is this necessary?

--return-code=warn      Warn about non-zero return codes (default)
--return-code=ignore	Do not print warning about return code
--return-code=fail	Exit immediately if return code is non-zero

When the dnotify processes received SIGTERM/SIGwhatever, should it do
anything special to terminate children?

Go to background mode? --daemon/--background? Or recommend start-stop-daemon.

What happens if you remove the directory that you monitor? (FIXME below)

Recursive option should rescan directory when changed?
  --rescan
  rescan directory
    for each directory that still exists, ignore
    for each directory that no longer exists, well what happens? FIXME - test
    for each directory that is new, call add_directory (FIXME: where to insert?)
    how to know what directories are old? how to search?

Add option to not replace {}? Allow escaping with backslash?
