v0.1.0: New and Improved Intermediate Format

This release introduces a new intermediate format for docker_build, which does not rely on the docker save format (unless you bazel run or build :foo.tar). You can see the gory details in intermediate-form.md, but the performance of docker_pull => docker_build => docker_push should improve considerably because we avoid the unnecessary roundtrips to the docker save form.

To benefit from this, make sure you avoid @foo//image:image.tar or //my/build:label.tar references, opting for: @foo//image or //my/build:label references instead.

The goal of this release was to dramatically improve the cycle times for edit/rebuild/repush and no-edit/rebuild/repush. With this release, we are able to demonstrate edit cycle times of <5 seconds across several Bazel languages.