fix(CONTRIBUTING): Developer Certificate of Origin w/o Grant

In 7fb55f77250a9b52b0515a7e655ecc605ae452ca the DCO lost the grant so
change the title back to just DCO.

Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)
Swap Firefox to Iceweasel so that the Desktop Integration example is simplified and easier to understand

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Adjust test to match its comment

Docker-DCO-1.1-Signed-off-by: Andrew Williams <williams.andrew@gmail.com> (github: TheDude05)
Add better ".git" detection and use

This way, packagers can set GIT_DIR appropriately if they'd prefer to not have ".git" inside their working directory.

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
bring back the explaination of our LGTM process

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
devicemapper: Fix tests on fedora

If /dev/loop-control exists on the system running the test then
ioctlLoopCtlGetFree() will be called, but if not it won't.  It does
not exist in the standard docker build environment, so the tests
currently require this to not be called. This makes it instead
optional, allowing the tests to run on e.g. Fedora.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
devmapper: Fix shutdown warnings

Shutdown contains debug warnings like:

[debug] deviceset.go:699 [deviceset docker-0:33-17945897] waitRemove(/dev/mapper/docker-0:33-17945897-pool)
[debug] deviceset.go:380 libdevmapper(3): libdm-common.c:552 (-1) Device /dev/mapper/docker-0:33-17945897-pool not found

This is because shutdown is using removeDeviceAndWait() to remove the pool device and the
wait part fails because the pool is gone.

We fix this by adding a pool specific removal function which avoids all the trickiness of the
normal remove.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
devmapper: Remove byHash hack

We no longer pass "pool" anywhere that uses byHash() per the last
commit, so we can now remove this hack.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Ensure docker cp stream is closes properly
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Move docker version introspection to a sub-package.

This facilitates the refactoring of commands.go.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Move even more stuff into dockerversion

Also, use it in all the places. :)

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
rewrite the PostgreSQL example using a Dockerfile, and add details to it

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #74 from tianon/more-separate

Move even more stuff into dockerversion
Merge pull request #4050 from SvenDowideit/put-back-LGTM

bring back the explanation of our LGTM process
Merge pull request #4034 from SvenDowideit/postgres-example

rewrite the PostgreSQL example using a Dockerfile, and add details to it
New package `nat`: utilities for manipulating the text description of network ports.

This facilitates the refactoring of commands.go

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

Docker-DCO-1.1-Signed-off-by: Andy Rothfusz <github@developersupport.net> (github: metalivedev)
Fix the one spot I missed dockerversion

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #75 from tianon/fix-my-broken-eagle

Fix the one spot I missed dockerversion
Merge pull request #4079 from shykes/separate-nat

New package `nat`: utilities for manipulating the text description of network ports