Update nodejs_web_app.md

The image centos:centos6.4 doesn't exist. Instead you have to choose between the official centos6 or centos7. Both images does not work together with de yum npm install. When choosing an centos6.5 from another distributor (tutum) it works.
integcli: add some more docker utils

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
integcli: use dockerCmdInDir in build tests

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

Updated to documentation to use the centos6 image instead of the unofficial tutum image of centos6.4
Print about "copy volume content" test passing

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Added "Github Submodules" section to Automated Builds doc.

Signed-off-by: Hollie Teal <hollie.teal@docker.com>
Add contrib/nuke-graph-directory.sh script to clean out old /var/lib/docker directories much more easily

Signed-off-by: Andrew Page <admwiggin@gmail.com>
style, grammar, spelling fixes.

Signed-off-by: Marc Tamsky <mtamsky@gmail.com> (github: tamsky)
Update libcontainer to 5589d4d879f1d7e31967a927d3e

Signed-off-by: Michael Crosby <michael@docker.com>
Made requested changes (capitalization)
add warning re: changing value of `dm.basesize`.

Signed-off-by: Marc Tamsky <mtamsky@gmail.com> (github: tamsky)
Move "image_export" to graph/export.go

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "image_history" to graph/history.go

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "images" to graph/list.go

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "viz" to graph/viz.go

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "load" to graph/load.go

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "import" to graph/import.go

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "image_delete" to daemon/image_delete.go

Note: this cannot yet be moved to graph/ because of a lingering
dependency on daemon. This has been noted in a FIXME.

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move "image_tag" and "tag" to graph/tag.go

Note: these 2 jobs should be merged into one. This was noted in a FIXME.

Signed-off-by: Solomon Hykes <solomon@docker.com>
Move some integration tests to integration-cli

Signed-off-by: Tibor Vass <teabee89@gmail.com>