Fix support for registry auth with Dockerfile build.

Docker-DCO-1.1-Signed-off-by: Jake Moshenko <jake@devtable.com> (github: jakedt)
add a little info about ghosts

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
docs: move security article to a new 'articles' section

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: move 'vagrant' install docs to the more accurate 'mac' install docs

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: change topic of windows install docs to 'install docker on windows'

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: instead of a top-level 'upgrading docker' doc, add an 'upgrades' paragraph to each installation target

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: remove out-of-date kernel requirements document.

Requirements differ from platform to platform depending on the plugins used, and so should be documented separately for each target platform

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: reuse official dependencies list from packager's guide for custom binary install docs
Reordering to make FAQ last
docs: simplify basic usage doc, step 1: check your docker install

docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: move a sysadmin-focused topic out of the basic usage manual and into installation docs (setting up a user group for non-root access)

docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: add standard 'check your docker install' paragraph to the 'hello world' examples.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
docs: "first steps with docker" is a better title than "learn basic commands"

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Docs: move advanced topic "create your own base image" out of basic user guide

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