Include instruction for AMI 2014.03

Include instructions to install Docker from Amazon's Software Repository on new AMI 2014.03 (Release Candidate)

Docker-DCO-1.1-Signed-off-by: Sebastien Stormacq <sebastien.stormacq@gmail.com> (github: sebsto)
Use https://get.docker.io/ubuntu consistently

The install script (on https://get.docker.io/) installs an APT sources.list
entry referencing an HTTPS repository, and takes care of installing the
apt-transport-https package. However, the Debian/Ubuntu specific installation
script (on https://get.docker.io/ubuntu) used an HTTPS repository but without
installing that package, causing the installation to fail on some platforms.

This will use HTTPS everywhere, and updates the documentation accordingly.

Docker-DCO-1.1-Signed-off-by: Jérôme Petazzoni <jerome@docker.com> (github: jpetazzo)

Docker-DCO-1.1-Signed-off-by: Jérôme Petazzoni <jerome@docker.com> (github: jpetazzo)
Move -o cli flag and DriverConfig from HostConfig
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Remove selinux build tag
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Add more label checks for selinux enabled
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Ensure that selinux is disabled by default

This also includes some portability changes so that the package can be
imported with the top level runtime.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Remove and unexport selinux functions
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #5058 from crosbymichael/remove-opts

Remove -o cli flag and DriverConfig from HostConfig
Merge pull request #4715 from sebsto/patch-1

Include instruction for AMI 2014.03
Merge pull request #4997 from jpetazzo/apt-should-always-use-https

Use https://get.docker.io/ubuntu consistently