Add all changes necessary for hashdeep to validate

Signed-off-by: Alex Nelson <a.nelson@prometheuscomputing.com>
Merge pull request #11 from ajnelson/archive/for_hashdeep_v1

Add support for validating rusage element, and Hashdeep (md5deep, etc.)

Acked-by: Simson Garfinkel <simsong@acm.org>