* Savernik: switch to ignore the file list checksum
  such that I *can* generate/manipulate lists with external tools.

* 7z support

* OffMirror::ChangeAttr::{my_chown,my_chgrp} use chown|chgrp commands;
  use system calls instead.
  Symlink problem - lchown needed as perl function.
* PROFILE: why BEGIN called from diff_list() 4 times per record?

