Add ENV['DOCKER_HOST'] as default socket and add docs
Add `--cpuset` option to kitchen-docker driver

This allows use of the docker `--cpuset` option in order to set cpu
affinities for suite containers. It also introduces a mechanism for checking
the current docker version as this feature is only available >= 1.1.0.
Add documentation for cpuset option in kitchen-docker
Remove ssh tcp check.

Kitchen docker uses the "wait_for_sshd" method in Test Kitchen to
determine when the container is available to ssh into. Since the Docker
server builds containers with SSH access on random ports, this presents
a problem when on networks that deny TCP checks to these ports.

As a workaround, I implemented an alternative that checks the state of
the Docker container to determine if it is up.
Remove logger.info message.
Adds --name and --link options
Add -P(--publish-all) option
Correct description of publish_all option
added a stderr redirect to the docker binary check because docker on OSX uses stderr to print output and ruby is interpretting this as an error
set use_sudo flag to false when using the run command to check if docker exists
tell verify_dependencies to be quieter

Running anything `kitchen`-related with kitchen-docker now produces lengthy stderr output, which makes it harder to see things.

Add redirection for STDERR when running the docker binary, as now running the `docker` command outputs to STDERR (version 1.2.0).
This is addressed in a [not-yet-released commit](https://github.com/docker/docker/commit/61b129d81802e3c988cc0e67e488b24968dd748a) where the `help` command is redirected.
added gentoo support
enable ssh PasswordAuthentication

on gentoo PasswordAuthentication is disabled in the default
configuration for security reasons, we have to enable it.
added emerge and paludis support for gentoo
added missing sudo for gentoo
add check for valid container id
update dns flag, make inspect command quieter
Merge branch 'master' of https://github.com/peterabbott/kitchen-docker
Add ENV['DOCKER_HOST'] as default socket and add docs
added a stderr redirect to the docker binary check because docker on OSX uses stderr to print output and ruby is interpretting this as an error