FIX: Linux mint troubleshooting tip

Package is called 'cgroup-lite' not 'cgroups-lite'. Verified on Linux Mint 16.

Ref http://packages.ubuntu.com/search?keywords=cgroup-lite

Docker-DCO-1.1-Signed-off-by: Dan Williams <me@deedubs.com> (github: deedubs)
don't skip cert check for an example & use HTTPS

This changes two URLs from http to https and it fixes a Dockerfile to
stop skipping certificate validation. It also adds the ca-certificates
package to that Dockerfile example.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Add back the Ubuntu "Memory and Swap Accounting" section that was lost when the "Kernel" page was culled

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
lets talk about the other way to make base images

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Fix misspelling

Docker-DCO-1.1-Signed-off-by: Adrian Mouat <adrian@adrianmouat.com> (github: amouat)
docs: explain DNS warnings & how to fix them

This explains how to fix the DNS warnings on Ubuntu and why they're
shown.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
forbid chained onbuild, from & maintainer triggers

This changes the way onbuild works:
- forbids the chaining of onbuild instructions
- forbids the use of `onbuild from`
- forbids the use of `onbuild maintainer`

It also makes docker throw errors when encountering such triggers when
executing the triggers during `FROM`.

Three tests have been added:
- ensure that chained onbuild (`onbuild onbuild`) is forbidden
- ensure that `onbuild from` is forbidden
- ensure that `onbuild maintainer` is forbidden

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Fix build command auth by adding the auth config and registry objects to the build job environment.

Docker-DCO-1.1-Signed-off-by: Jake Moshenko <jake@devtable.com> (github: jakedt)
Merge pull request #4265 from unclejack/explain_networkmanager_and_dns_problems

docs: explain DNS warnings & how to fix them
Merge pull request #4252 from SvenDowideit/mention-scratch-image

lets talk about the other way to make base images
Merge pull request #4261 from amouat/patch-1

Fix misspelling
Merge pull request #4251 from tianon/add-back-grub-info

Add back the Ubuntu "Memory and Swap Accounting" section that was lost when the "Kernel" page was culled
Merge pull request #4233 from deedubs/patch-1

FIX: Linux mint troubleshooting tip
reinforce that docker build --rm is a good default to use

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Merge pull request #4273 from SvenDowideit/docker-build-rm

reinforce that docker build --rm is a good default to use
small update to API docs to go with #4276

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #4248 from unclejack/https_fixes

don't skip cert check for an example & use HTTPS
Fix cli argument usage typo for docker --mtu

Docker-DCO-1.1-Signed-off-by: Danny Berger <dpb587@gmail.com> (github: dpb587)
Merge pull request #4260 from unclejack/onbuild_fixes

forbid chained onbuild, from & maintainer triggers
Merge pull request #4271 from DevTable/fixbuildauth

Fix build auth by adding config to the build job environment