Do some forward porting of the old work of
mitchellh/packer's docker branch. #774
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
Rename docker post processor to docker-push.

Implement login to a docker registry, error handling
Finish up parameter parsing and validation.

Login to a docker index now works, ready for
implementation of the actual push logic.
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
Add docker-import post-processor.

Implemented initial working version
of Docker image importing code. #774
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
website: update defaults for DO ID's
Start adding dockerfile provisioning to docker-import post-processor #774
docker-import post-processor, add TODO #774
docker-import: finish up Dockerfile provisioning, Add TODO for next section #774
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
docker-import + docker-push: Add some beginning tests.  #774
docker-push: add code to handle seperate registry, push a specific repository/tag #774
Merge branch 'master' of https://github.com/mitchellh/packer into docker-metadata
Merge branch 'docker-metadata' of https://github.com/mmckeen/packer into mmckeen-docker-metadata
post-processor/docker-import: refactor

/cc @mmckeen - Did a refactor here, CC'd in case you're curious
or want to learn :)