Add README.md file for the docker directory

See issue #5873

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
utils: add test for TimeoutConn

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
Add integration test for history command and fix bug where history
would occasionally be returned in the incorrect order if sequential
layers had the same created time.

Docker-DCO-1.1-Signed-off-by: Bryan Murphy <bmurphy1976@gmail.com> (github: bmurphy1976)
Now using the nginx docker image instead of the apache one. dotcloud/docker/issues/6374

Docker-DCO-1.1-Signed-off-by: Julien Bordellier <me@julienbordellier.com> (github: jstoja)
adding a little uniqueness, to wrapped errors.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Add security message to readme
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
pin awscli to 1.3.9, and then complexify the sync's to make them more likely to complete

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
compared the 0.11 sitemap to the 1.0 one and these are the differences

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
fixed docker port command
Merge pull request #6500 from leeplay/userguide

fixed docker port command
use a numbered list for maintainers responsibility

At the moment maintainers responsibility are spelled out with a hybrid
list. I.e. an unordered list with an associated number.

In this commit I the number list proper is used.

Docker-DCO-1.1-Signed-off-by: Daan van Berkel <daan.v.berkel.1980@email.com> (github: dvberkel)
Merge pull request #6468 from jstoja/6374-docs-apache-image

Docs: apache image on installation
Merge pull request #6499 from SvenDowideit/add-redirects-for-renames

compared the 0.11 sitemap to the 1.0 one and these are the differences
Merge pull request #6497 from SvenDowideit/awscli-changes

pin awscli to 1.3.9, and then complexify the sync's to make them more li...
Merge pull request #6487 from vbatts/vbatts-error_info

adding a little uniqueness, to wrapped errors.
Wrap lines in security notice
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Fix go vet errors

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #6495 from vieux/pr_6269

Fix go vet errors
Merge pull request #6399 from dvberkel/master

use a numbered list for maintainers responsibility
Merge pull request #5878 from timthelion/docs-docker-readme

Add README.md file for the docker directory