Added sysvinit/sysconfig files for redhat family of distros (RHEL/CentOS/SL/etc.)

Docker-DCO-1.1-Signed-off-by: Adam Miller <admiller@redhat.com> (github: maxamillion)
Merge branch 'master' into maxamillion/add_redhat_sysvinit

* master: (64 commits)
  Move the canonical run configuration objects to a sub-package
  Remove useless code in client implementation of 'run'.
  pkg/opts: a collection of custom value parsers implementing flag.Value
  Move api-specific code to the api package
  Fix the tests, too
  Fix the one spot I missed dockerversion
  fix underline/heading
  New package `nat`: utilities for manipulating the text description of network ports.
  rewrite the PostgreSQL example using a Dockerfile, and add details to it
  Move even more stuff into dockerversion
  fix underline/heading
  Move docker version introspection to a sub-package.
  add port forwarding notes for mac/boot2docker docs
  Update remote_api_client_libraries.rst
  Avoid extra mount/unmount during container registration
  add a little more information about the docker run -P option
  lxc: Drop NET_ADMIN capability in non-privileged containers
  devmapper: Remove directory when removing devicemapper device
  add a little info on upgrading
  point out that ENV DEBIAN_FRONTEND will persist, so its not recommended
  ...
Merge pull request #3947 from maxamillion/maxamillion/add_redhat_sysvinit

Add sysvinit/sysconfig files for redhat family of distros (RHEL/CentOS/SL/etc.)
Refactor utility `MkBuildContext` to the more generic `archive.Generate`

This facilitates refactoring commands.go.

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