Adds Docker Image v1 Spec Documention

Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
Trying to keep transport and name separate is fine, but the Docker client today will interpret "localhost:123/hello" and "localhost:456/hello" to be different images, so the spec needs to treat them as different as well.