Apply @jamtur01's copy edit's to certificates.md

Docker-DCO-1.1-Signed-off-by: Timothy <timothyhobbs@seznam.cz> (github: timthelion)
Docs: articles/certificates.md rewrite.

This commit contains a re-structured re-write of the original
certificated.md file, containing the amendments proposed with
PR #7120 (commit ID bd28595e310ccfa98) by @timthelion.

Related to: https://github.com/dotcloud/docker/pull/7120

2014-07-30: Update/rebase/squash based on the comments from @jamtur01 and @fredlf.
2014-08-12: Update/rebase/squash based on the comments from @fredlf (of 2014-08-12).

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Added fredlf's suggested changes.

Signed-off-by: Hollie Teal <hollie@docker.com>
Removed merge conflict artifacts.

Signed-off-by: Hollie Teal <hollie@docker.com>
Updated CentOS documentation to reflect CentOS 7 install.
Added reference to CentOS Dockerfiles on github.

Signed-off-by: Jim Perrin <jperrin@centos.org> (github: jperrin)
Update docker-attach.1.md
Merge pull request #7126 from ostezer/update-certificates

Docs: articles/certificates.md rewrite.
Fix race condition in sending started signal from monitor

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Fix race between container cleanup and inspect/ps

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Fix race on state serialization

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Cleanup: Make channels unbuffered

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Merge pull request #7582 from LK4D4/fix_races

Fix some race conditions
Cleanup: move image depth checks in image/

Signed-off-by: Solomon Hykes <solomon@docker.com>
Merge pull request #7546 from hollietealok/master

Added fredlf's suggested changes.
Merge pull request #7562 from jperrin/master

Updated CentOS documentation to reflect CentOS 7 install.
Merge pull request #7581 from samuel-phan/patch-1

Update docker-attach.1.md
Remove crashTest.go since the use case is covered by docker-stress

Signed-off-by: Andrew Page <admwiggin@gmail.com>
Merge pull request #7593 from tianon/remove-crashtest

Remove crashTest.go since the use case is covered by docker-stress
Merge pull request #7589 from shykes/cleanup-img-depth

Cleanup: move image depth checks in image/
remove empty builder folder

Signed-off-by: Victor Vieux <vieux@docker.com>