Get an extra pair of eyes on the Softlayer installation docs

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Standardize "apt-get install" usage across the repo

I might have missed some, but I think this is most of the offenders.

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Move Server.ContainerAttach to Daemon.ContainerAttach

This is part of an effort to break apart the legacy server package. Help wanted!

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
New job "log": logs a new event

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Move "pause" to daemon/pause.go

This is part of an effort to break apart the deprecated server/ package

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Move "unpause" to daemon/pause.go

This is part of an effort to break apart the deprecated server/ package

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Docs: articles/https minor amendments and update

This commit proposes some minor amendments and updates
for the articles/https.md document to fix certain errors, inc.:

 - Marking commands / flags as code (e.g. `tlsverify`) [done before rebase]
 - Capitalising the word Docker
 - Normalizing headers to match the rest of the docs;
 - Expanding the page description to match the page title and the content;
 - Capitalizing HTTPS etc.;
 - Some spelling error fixes;
 - Line-length adjustments to make it easier to read the raw file.

It does not propose any fundemental changes to the structure of the document.
Certain changes were based before another update on this doc.

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Bump libcontainer dep

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Add support for autodetected HOME from USER (if HOME is unset)

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Remove pkg/user now that it's embedded in libcontainer

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Update TestEnvironment to explicitly set "HOME" to be empty so it gets autofilled

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #7327 from ostezer/fix-articles-https

Docs: articles/https minor amendments and update
Merge pull request #7152 from SvenDowideit/get-help-maintaining-softlayer-docs

MAINTAINERS: Get an extra pair of eyes on the Softlayer installation docs
Remove the restriction on multi-user PRs

This came up in #docker-dev today.  We're not sure exactly why the original restriction was put it place.  It is not well obeyed.  Please comment if you know the origin of the restriction.

Docker-DCO-1.1-Signed-off-by: Timothy Hobbs <timothyhobbs@seznam.cz> (github: timthelion)
Fix .dockerignore when ignoring unreadable dirs

The initial `ValidateContextDirectory` implementation fails loudly when a file
lacks read permissions in the current context. However that situation is valid
if the file is included in the `.dockerignore` patterns.

Docker-DCO-1.1-Signed-off-by: Bruno Renié <brutasse@gmail.com> (github: brutasse)
Return error for utils.Matches in archive
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Merge pull request #7357 from crosbymichael/docker-ignore

Fix .dockerignore when ignoring unreadable dirs
Merge pull request #7312 from tianon/update-libcontainer

Bump libcontainer dep
Merge pull request #7344 from shykes/cleanup-server-attach

Move container-related jobs out of deprecated server/ package
Merge pull request #7354 from timthelion/patch-8

Remove the restriction on multi-user PRs