Add ability to refer to an image by repository name and digest using the
format repository@digest. Works for pull, push, run, build, and rmi.
Signed-off-by: Andy Goldstein <agoldste@redhat.com>
Now that the archive package does not depend on any docker-specific
packages, only those in pkg and vendor, it can be safely moved into pkg.
Signed-off-by: Rafe Colton <rafael.colton@gmail.com>
