add --all-tags to pull & pull latest by default

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
add a little documentation for docker pull

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
docker build: pull just latest if tag uspecified

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Update docker_remote_api_v1.14.md

It is a tar stream, you should mention that somehow.

Here is the proof:

```
	host:~$ docker run -t -i ubuntu:14.04 bash
	root@c39be4c7b7c8:/# echo "my file contents" > abc
	root@c39be4c7b7c8:/# cat abc
	my file contents
	root@c39be4c7b7c8:/# exit
	host:~$ curl -H "Content-Type: application/json" -d '{"Resource":"/abc"}' http://localhost:4500/containers/c39be4c7b7c8/copy
	abc0100644000000000000000000000002112402102531007674 0ustar0000000000000000my file contents
	host:~$ curl -H "Content-Type: application/json" -d '{"Resource":"/abc"}' http://localhost:4500/containers/c39be4c7b7c8/copy > response_content
	  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
	                                 Dload  Upload   Total   Spent    Left  Speed
	100  2067  100  2048  100    19  56968    528 --:--:-- --:--:-- --:--:-- 58514
	host:~$ tar xvf response_content
	abc
	host:~$ cat abc
	my file contents
```

Docker-DCO-1.1-Signed-off-by: Mustafa Akın <mustafa91@gmail.com> (github: SvenDowideit)
Update export, copy and build API to sat 'TAR STREAM' for all versions.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Very minor formatting update for docs/sources/articles/networking.md

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Added --device flag to run reference

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Merge pull request #7759 from unclejack/pull_latest_by_default

make docker pull only the latest tag by default
Merge pull request #7929 from SvenDowideit/doc-tar-stream

Sven Dowideit 	Update export, copy and build API to say 'TAR STREAM' for all versions.
Merge pull request #7930 from jamtur01/nformat

Very minor formatting update for docs/sources/articles/networking.md
Merge pull request #7931 from jamtur01/device

Added --device flag to run reference
Make the side bar about in-document navigation by removing the duplicated h1

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Merge pull request #7949 from SvenDowideit/remove-doubled-up-page-heading

Make the side bar about in-document navigation by removing the duplicated h1
Change default label of container volumes to shared SELinux Label

Since these will be shared between containers we want to label
them as svirt_sandbox_file_t:s0.  That will allow multiple containers
to write to them.

Currently we are allowing container domains to read/write all content in
/var/lib/docker because of container volumes.  This is a big security hole
in our SELinux story.

This patch will allow us to tighten up the security of docker containers.

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)