Import public GPG key after adding the openSUSE repository

Docker-DCO-1.1-Signed-off-by: Christian Berendt <berendt@b1-systems.de> (github: berendt)
Allow / as source of -v

We discussed this at the docker plumbers meetup and for tools and
working on the system for things like boot2docker and coreos this is
needed.  You can already bypass this check so we felt it is ok to start
allowing this feature.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Remove api test for bind mount /
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Remove superfluous reptition from usingdocker.md

Clarify wording about default docker ps options

Fix typo in dockerlinks.md

Docker-DCO-1.1-Signed-off-by: Paul Weaver <pauweave@cisco.com> (github: ch3pjw)
Update nodejs_web_app.md

Docker-DCO-1.1-Signed-off-by: Hyeongkyu Lee <hyeongkyu.lee@navercorp.com> (github: leeplay)
Merge pull request #6712 from SvenDowideit/pr_out_remove_superfluous_reptition_from_usingdocker_md

Remove superfluous reptition from usingdocker.md
Merge pull request #6676 from berendt/opensuse_import_public_gpg_key

Import public GPG key after adding the openSUSE repository
Merge pull request #6716 from leeplay/master

Update nodejs_web_app.md
Update dockerizing.md

fix typo
Merge pull request #6718 from mchelen/patch-1

Update dockerizing.md
mkimage: use /var/tmp by default instead of /tmp

Additionally, this can be overridden by setting the TMPDIR variable,
like this was already the case for the generic `mkimage.sh` script.

As explained in #6456, the rationale to use `/var/tmp` instead of `/tmp`
is that `/tmp` is often a small tmpfs filesystem with more restricted
rights.

Docker-DCO-1.1-Signed-off-by: Vincent Bernat <vincent@bernat.im> (github: vincentbernat)
Merge pull request #6729 from vincentbernat/fix/mkimage-use-var-tmp

Update mkimage scripts to use /var/tmp by default instead of /tmp
Merge pull request #6701 from crosbymichael/mount-root

Allow / as source of -v
Adds check if default ip address is correct format.

It avoids hidden error when ports are redirected from
container to host using -p host_port:guest_port.

Docker-DCO-1.1-Signed-off-by: Jiří Župka <jzupka@redhat.com> (github: jzupka)