Fix registry pushing/tagging

* docker push host:port/namespace/repo wouldn't push multiple tags for
  the same image
* getImageList was unnecessarily complex returning a nested array of
  ImgData when a correctly ordered list of images was sufficient
* removed various bits of redundancy

Docker-DCO-1.0-Signed-off-by: Danny Yates <danny@codeaholics.org> (github: codeaholics)
Remove unneeded DependencyGraph

Docker-DCO-1.0-Signed-off-by: Danny Yates <danny@codeaholics.org> (github: codeaholics)
Further simplification

Docker-DCO-1.0-Signed-off-by: Danny Yates <danny@codeaholics.org> (github: codeaholics)
Fix indentation to match rest of file (tabs, not spaces)

Docker-DCO-1.0-Signed-off-by: Danny Yates <danny@codeaholics.org> (github: codeaholics)
gofmt

Docker-DCO-1.0-Signed-off-by: Danny Yates <danny@codeaholics.org> (github: codeaholics)
Merge branch 'fix-registry-push-tags' of https://github.com/codeaholics/docker into codeaholics-fix-registry-push-tags

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Make sure new repositories can be pushed with multiple tags

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #3684 from crosbymichael/push-multiple-tags

Push multiple tags for repository