Improved X-Registry-Auth content instructions

Hi,

this is a small contribution to fix some slightly unprecise information about the `X-Registry-Auth` header required to pull from private registries through the remote API. After a lot of trial and I error I managed to find that the documentation indications had this issues:

* Apparently single quotes cannot be used and double quotes (regular JSON) is required.
* Also the `auth` key must be passed even if empty or a 403 will result.
* It was not clear what the `serveraddress` had to be.

I added some small clarifications for anyone taking a look at the docs to keep them from the problems I've encountered. Hope this is helpful.

Thanks to all the contributors for bringing so much awesomeness to the linux world. :)

Signed-off-by: David Pelaez Tamayo <hello@davidpelaez.me>
It seems that we need these 2 options enabled for both aufs and devicemapper drivers when running on EXT4 - so test for them

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Update remote_api_client_libraries.md

Ordering all clients alphabetically, by language.
Including all available languages in `page_keywords`.

Signed-off-by: Abhinav Ajgonkar <abhinav316@gmail.com>
hack/install.sh: install apparmor when enabled

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
add the timeutils package

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #8080 from SvenDowideit/test-for-ext4-fs-kernel-options

It seems that we need these 2 options enabled for both aufs and devicema...
use custom marshalling for JSONLog

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #8083 from unclejack/install_apparmor

hack/install.sh: install apparmor when enabled
Add "hack/install.sh" to the "PRs welcome" note in the end of the install script

Also, simplified the output method by using `cat >&2 <<EOF ...` instead of multiple lines of `echo >&2 '...'`.

Signed-off-by: Andrew Page <admwiggin@gmail.com>
move stdcopy to pkg/stdcopy

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
stdcopy: improve perf by avoiding buffer growth

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Benchmark for StdWriter.Write

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Merge pull request #6 from LK4D4/benchmark_for_8084

Benchmark for StdWriter.Write
Merge pull request #8085 from tianon/hack-install-location

Add "hack/install.sh" to the "PRs welcome" note in the end of the install script
Merge pull request #8084 from unclejack/improve_stdcopy

stdwriter: improve perf by avoiding buffer growth
integcli: run build tests in tmpdir

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #8088 from unclejack/integcli-keep_permissions

integcli: run inaccessible context test in tmpdir
tarsum: name collision fix

If a tar were constructed with duplicate file names, then depending on
the order, it could result in same tarsum.

Signed-off-by: Vincent Batts <vbatts@redhat.com>
Merge pull request #7889 from vbatts/vbatts-tarsum_name_collision

tarsum: name collision fix
Removed runconfig.ParseSubcommand

 Removed runconfig.ParseSubcommand, changed it to runconfig.Parse and editted related tests and modules

Signed-off-by: Oh Jinkyun <tintypemolly@gmail.com>