Update documentation noting that SIGCHLD is not proxied.

Docker's --sig-proxy option sends all signals but one to a container. The
exception s SIGCHLD, which is deliberately ignored as it doesn't make sense to
send such a signal to a process in a container. Documentation updates will make
this less confusing if anyone does attempt to do this.

Docker-DCO-1.1-Signed-off-by: Matt Heon <mheon@redhat.com> (github: mheon)
Add a step to verify if Docker is working as expected

Like in the other installation guides I added a simple test
to verify that importing images and starting containers is
working.

Docker-DCO-1.1-Signed-off-by: Christian Berendt <berendt@b1-systems.de> (github: berendt)
add Docker version and branch to html header

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)
Restrict portallocator to Docker allocated ports

Port allocation status is stored in a global map: a port detected in use will remain as such for the lifetime of the daemon. Change the behavior to only mark as allocated ports which are claimed by Docker itself (which we can trust to properly remove from the allocation map once released). Ports allocated by other applications will always be retried to account for the eventually of the port having been released.

Docker-DCO-1.1-Signed-off-by: Arnaud Porterie <icecrime@gmail.com> (github: icecrime)
Make ErrPortAlreadyAllocated an error interface with a few extras,
adjust tests to fit.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
Use last allocated port logic in port allocator

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
portmapper: unit tests for remap problem

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
remove deprecated syntax for docker commit

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Remove extra "Docker" from docs index
Merge pull request #6761 from fgrehm/patch-1

Remove extra "Docker" from docs index
Merge pull request #6631 from SvenDowideit/add-versioning-to-docs-output

Add versioning to docs output
use the official  image for now - there's an opensuse image on its way

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Formatting and consistency fixes to CLI and RUN references

* Removed double backticks.
* Reformatted paragraphs.
* Fixed consistent STDOUT/STDIN/STDERR references.
* Fixed several broken URLs.
* Fixed backtick mismatches.

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Merge pull request #6544 from mheon/sigproxy_docs

Update --sig-proxy documentation
Add the 1.13 API docs to the menu

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #6768 from SvenDowideit/add-1.13-api-to-docs-menu

Add the 1.13 API docs to the menu
Merge pull request #6765 from SvenDowideit/pr_out_use_the_official_image_for_now_there_s_an_opensuse_image_on_its_way

use the official  image for now - there's an opensuse image on its way
Merge pull request #6766 from jamtur01/clirun

Formatting and consistency fixes to CLI and RUN references
Merge pull request #6682 from erikh/6476-persistent_port_allocation

fix persistent port allocation
Merge pull request #6742 from vieux/remove_deprecate_syntax

remove deprecated syntax for docker commit