Add Developer Certificate of Origin Text

We purposely chose to license Docker under the Apache 2.0 license. This is a well-known
license, which is popular for its permissive and flexible properties, while still
encouraging a collaborative community. It also makes certain representations with regard
to contributions, and the rights given to contributors, the project, people who use Docker,
people who modify Docker, etc.

This approach to contributions is inspired by the popular Linux Developer
"Certificate of Origin". This approach makes it simple for new contributors to get started,
and avoids bureaucracy in tracking contributions and contributors.

To indicate accordance, each individual contribution to the Project is signed off by the
developer, using his or her real name, email address, and github handle in the format below:

	Docker-DCO-1.0-Signed-off-by: Joe Smith <joe.smith@email.com>
Merged with master
Add more TestBuild Dockerfiles, especially for making sure manual RUN echo '#!...' continues to work correctly
install instructions use unprefixed fedora image

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
Check standalone header when pinging a registry server. Standalone has to be true to use basic auth (in addition to previous requirements)
Fix #3149: port mapping of TCP + UDP

Signed-off-by: Tzu-Jung Lee <roylee17@gmail.com>
Update instructions for mtu flag for Docker on GCE
Fixed error in group add example

There is no ${USERNAME} in bash, only ${USER}
Simplified and streamlined Amazon Quickstart

The amazon quickstart images are EBS backed and include cloudinit. I've personally tested these documentation changes as a new user to Docker.
Tweak formatting for GCE instructions
fix error on docker wait
Fixed registry unit tests
Fix dotCloud to Docker, Inc
Merge pull request #3388 from tianon/more-build-tests

Add more TestBuild Dockerfiles, especially for 'echo shebang' testing
Move utility package 'iptables' to pkg/iptables
Merge pull request #3328 from shykes/pkg-iptables

Move utility package 'iptables' to pkg/iptables
[docs] Fix for wrong version warning on master instead of latest.
Merge pull request #3473 from dhrp/docs-version-warning-fix

[docs] Fix for wrong version warning on master instead of latest.
Remove the @github handle as it generates emails.
Update REMOTE_TODO.md