check if the daemon is run as root on startup

This commit makes Docker throw an error if the daemon isn't started as
root.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
update AUTHORS

Docker-DCO-1.1-Signed-off-by: Bryan Matsuo <bryan.matsuo@gmail.com> (github: bmatsuo)
FIXES #5398: pkg/graphdb build only dependent on cgo tag

Docker-DCO-1.1-Signed-off-by: Bryan Matsuo <bryan.matsuo@gmail.com> (github: bmatsuo)
remove when httputil.NewClientConn when not in hijack

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
move hijack to it's own file

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
fix https

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
add _ping endpoint

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
add doc

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
return write error

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
engine: catchall handler is shadowed by specific handlers

This allows using `Engine.Register` and `Engine.RegisterCatchall` on the
same engine without the catchall hiding all other handlers.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Engine: empty job names are illegal, catchall or not

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Move 'auth' to the registry subsystem

This is the first step towards separating the registry subsystem from
the deprecated `Server` object.

* New service `github.com/dotcloud/docker/registry/Service`
* The service is installed by default in `builtins`
* The service only exposes `auth` for now...
* ...Soon to be followed by `pull`, `push` and `search`.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Move 'search' to the registry subsystem

This continues the effort to separate all registry logic from the
deprecated `Server` object.

* 'search' is exposed by `github.com/dotcloud/docker/registry/Service`
* Added proper documentation of Search while I was at it

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
remove fixme

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Update vendored deps that have a proper version number to use said specific versions

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Update devenvironment.md

`git clone` should use `https` URL.
Merge pull request #5585 from lukemarsden/patch-1

git clone should use https URL in devenvironment.md
nat: Fix --expose protocol parsing

A command like:
 docker run --expose 5353/tcp -P fedora sleep 10

Currently fails with:
Error: Cannot start container 5c558de5f0bd85ff14e13e3691aefbe531346297a27d4b3562732baa8785b34a: unknown protocol

This is because nat.SplitProtoPort() confuses the order of the port and
proto in 5353/tcp, assuming the protocol is first. However, in all other
places in docker the protocol is last, so the fix is just to swap these.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Rearrange the existing info a little, and add example style guide

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Merge pull request #5587 from SvenDowideit/docs-examples-style-guide

Rearrange the existing info a little, and add example style guide