sync: check for metadata/newstuff; fixes #30 #31

- Use the master mirror when a metadata file is about to be synced, or
  for any files located in /newstuff; fixes GitHub issues #30 and #31
main: rearrange options POD; add FIXME for size check

- Rearranged the --verbose/--debug options into their own section
- Added POD for --debug-files option
- Added FIXME to re-check the size of the downloaded file after it's
  been moved from the tempfile, so the size can be compared with the
  archive file
Role::FileDir::Attribs: changed 'parent' to 'parent_path'
main: fixed issue with 'parent_path'; more debug output