Changes to 'copy_file()':
  * added support for making hard links and symlinks
  * noted that it silently clobbers existing files when copying, but
    blows up if destination exists when linking -- hmmm...
  * error message tweak
Added 'base_name' parameter to 'make_tarball()' and 'make_zipfile()'.
Added 'make_archive()' -- wrapper around 'make_tarball()' or
  'make_zipfile()' to take care of the archive "root directory".