docker rmi -f works with stopped containers + revamped error messages

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
update message

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
Update hack/dind to match the rest of our scripts

No functional changes here, just coding style and maintainability.

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Add notes about git commit messages

This improves readability of commits a lot and is easy to
follow. I think most people follow those rules already. They are based
on http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html

Docker-DCO-1.1-Signed-off-by: Johannes 'fish' Ziemke <github@freigeist.org> (github: discordianfish)
Make Jerome Petazzoni a maintainer for dind

In the spirit of getting more contributors to maintain their
components.. I nominate @jpetazzo ot maintain dind (he's the original
author).

@jpetazzo I don't expect this to be too much load, but it's a good and
symbolic start :)

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Fix bridge ip comparison

Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass)
Remove logger from nsinit struct
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Export SetupUser
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Remove statewriter interface, export more libcontainer funcs

This temp. expands the Exec method's signature but adds a more robust
way to know when the container's process is actually released and begins
to run.  The network interfaces are not guaranteed to be up yet but this
provides a more accurate view with a single callback at this time.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Add ability to set cgroups freezer
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #5512 from crosbymichael/set-freezer

Add ability to set cgroups freezer
Merge pull request #5511 from crosbymichael/refactor-libcontainer

Refactor: remove statewriter type and all callback for process start
Export syncpipe fields
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Split term files to make it easier to manage
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Export more functions from libcontainer
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Remove command factory and NsInit interface from libcontainer
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Integrate new structure into docker's native driver

This duplicates some of the Exec code but I think it it worth it because
the native driver is more straight forward and does not have the
complexity have handling the type issues for now.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Fix execin with environment and Enabled support
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Make native driver use Exec func with different CreateCommand
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
docker save: typo reference image, not container

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)