Move "possible config locations" list to the top of check-config.sh

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
engine.Installer: a standard interface for "installable" services

Installer is a standard interface for objects which can "install"
themselves an engine by registering handlers.

This can be used as an entrypoint for external plugins etc.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Remove the concept of a root dir out of engine

This makes the engine more general purpose so that we can
use it and the job routing functionality for reexec'ing our binary
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

Conflicts:
	integration/runtime_test.go
Update tests with engine root removal
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Fixed an missing '-' on the "--rm"

Docker-DCO-1.1-Signed-off-by: William Henry <whenry@redhat.com> (github: ipbabble)

 Changes to be committed:
	modified:   contrib/man/md/docker-build.md
Merge branch 'man1-assumption' of https://github.com/tianon/docker into manpages
Fixed some missing ']' and the TAG

Docker-DCO-1.1-Signed-off-by: William Henry <whenry@redhat.com> (github: ipbabble)

 Changes to be committed:
	modified:   contrib/man/md/docker-build.1.md
devicemapper: Don't mount in Create()

We used to mount in Create() to be able to create a few files that
needs to be in each device. However, this mount is problematic for
selinux, as we need to set the mount label at mount-time, and it
is not known at the time of Create().

This change just moves the file creation to first Get() call and
drops the mount from Create(). Additionally, this lets us remove
some complexities we had to avoid an extra unmount+mount cycle.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Merge pull request #5336 from tianon/slightly-more-organized-check-config

Move "possible config locations" list to the top of check-config.sh
Remove error from engine.New()

Without creating a root there is no way for the engine to return an
error from the new function.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Update link to interactive tutorial
Update link to interactive tutorial
Merge pull request #5347 from crosbymichael/engine-root

Remove root dir from engine
Merge pull request #5345 from shykes/engine-installer

engine.Installer: a standard interface for "installable" services
Merge pull request #5349 from ipbabble/manpages

Manpages - fixes and merged tianon/docker man1-assumption branch
Merge pull request #5362 from sindhus/patch-2

Update link to interactive tutorial
Docs auto-conversion fixes and MD marking and structure improvements.

 - Remove redundant chars and all errors caused by RST->MD conversion.
   e.g. [/#, /\, \<, />, etc.]
 - Fix broken inter-document links
 - Fix outbound links no-longer active or changed
 - Fix lists
 - Fix code blocks
 - Correct apostrophes
 - Replace redundant inline note marks for code with code marks
 - Fix broken image links
 - Remove non-functional title links
 - Correct broken cross-docs links
 - Improve readability

Note: This PR does not try to fix/amend:

 - Grammatical errors
 - Lexical errors
 - Linguistic-logic errors etc.

It just aims to fix main structural or conversion errors to serve as
a base for further amendments that will cover others including but
not limited to those mentioned above.

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)

Update:

 - Fix backtick issues

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Looking into some broken links, I noticed that we don't need to use
relative paths, and also fixed some broken images.

There are still more todo - next PR I think :)

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Merge pull request #5377 from SvenDowideit/fix-terms-links

Merged.
Merge pull request #5356 from alexlarsson/devmapper-no-mount-in-create

devicemapper: Don't mount in Create()