umoci 0.0.0~rc1

At this point, umoci implements enough functionality to be able to
extract, repack and modify OCI images. It is still missing major
functionality (such as the ability to create an entirely new image or
just create tags for images), but should be enough for a demo.

Please don't use this anywhere important. There are known security
issues with this release (which will be fixed before 0.0.0).

Signed-off-by: Aleksa Sarai [email protected]