Changes:
- Provide a summary of the generation method.
- Clarify that every file in the tree must be included.
- Manifests at the first level of the directory structure are now
  REQUIRED to help mitigate the cost of redistribution. Other levels are
  still optional.
- Scripts are permitted generate multiple levels of Manifests in
  parallel to save the cost of traversing the tree multiple times.

-- 
Robin Hugh Johnson
Gentoo Linux: Developer, Trustee & Infrastructure Lead
E-Mail     : robbat2@gentoo.org
GnuPG FP   : 11AC BA4F 4778 E3F6 E4ED  F38E B27B 944E 3488 4E85