main: show how 'tempdir' was determined/set
main: dump script arguments in main instead of Config
main: handle when 'ls-laR.gz' doesn't exist; fixes #35

- When the script is called with a --path that doesn't have an
  'ls-laR.gz' file, warn the user to either fix the path, or pass in
  the --create-mirror switch, so the script knows to create a mirror
  instead of thinking that the path is wrong (expecting ls-laR.gz to
  exist at --path)
main: fix display of MD5 checksum for non-existant ls-laR.gz