Add code for Pardot implementation to docs

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

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
beam/data: Message.GetOne() returns the last value set at a key

This is a convenience for callers which are only interested in one value
per key. Similar to how HTTP headers allow multiple keys per value, but
are often used to store and retrieve only one value.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Engine: Env.MultiMap, Env.InitMultiMap: import/export to other formats

* `Env.MultiMap` returns the contents of an Env as `map[string][]string`
* `Env.InitMultiMap` initializes the contents of an Env from a `map[string][]string`

This makes it easier to import and export an Env to other formats
(specifically `beam/data` messages)

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Engine: Receiver and Sender preserve Job.Env

When sending a new job to a `engine.Sender`, the corresponding
`engine.Receiver` will receive that job with its environment preserved.
Previously the job name, arguments and streams were preserved but the
env was lost.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
fix(daemon): ensure the /var/lib/docker dir exists

The btrfs driver attempts to stat the /var/lib/docker directory to
ensure it exists. If it doesn't exist then it bails with an unhelpful
log line:

```
2014/05/10 00:51:30 no such file or directory
```

In 0.10 the directory was created but quickly digging through the logs I
can't tell what sort of re-ordering of code caused this regression.

Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)
Dockerfile: updated ubuntu release used for builds

This patch just revs the Ubuntu release used for builds from 13.10
to 14.04.

Docker-DCO-1.1-Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> (github: cyphar)
Merge pull request #5716 from shykes/pr_out_engine_receiver_and_sender_preserve_job_env
Fix bug on LXC container start. Fixes #5718
Docker-DCO-1.1-Signed-off-by: Fernando Mayo <fernando@tutum.co> (github: fermayo)
Remove signal_freebsd (already in pkg/signal)

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume@charmes.net> (github: creack)
Use int64 instead of int

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume@charmes.net> (github: creack)
Integration test for link and unlink containers

Docker-DCO-1.1-Signed-off-by: Fabio Falci <fabiofalci@gmail.com> (github: fabiofalci)
Give the Redirect a HostName - filled in from the s3 bucket name.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
reduce cache time to 1 hours so future docs releases update the cloudfront caches faster

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
libcontainer: Create dirs/files as needed for bind mounts

If you specify a bind mount in a place that doesn't have a file yet we
create that (and parent directories). This is needed because otherwise
you can't use volumes like e.g. /dev/log, as that gets covered by the
/dev tmpfs mounts.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Merge pull request #5730 from SvenDowideit/fix-hostname-for-redirects

Give the Redirect a HostName - filled in from the s3 bucket name.
Merge pull request #5731 from SvenDowideit/reduce-cache-max-age

reduce cache time to 1 hours so future docs releases update the cloudfront caches faster
Merge pull request #5621 from ostezer/docs-add-pardot

Add code for Pardot implementation to docs
Merge pull request #5741 from creack/remove_unused_file-2

Remove signal_freebsd (already in pkg/signal)
Merge pull request #5729 from fabiofalci/link_unlink_test

Integration test for link and unlink containers