Docker integration

Currently we're making Docker as a first class citizen into Mesos (https://issues.apache.org/jira/browse/MESOS-1524). The current high level design is to utilize the docker cli for all the docker api integration and reuse the existing mesos executor for waiting on the container exit.

To try out the docker integration into Mesos feature, follow the following steps:

1, Grab the docker feature branch at https://github.com/mesos/mesos/tree/docker

2, Launch an TaskInfo with its CommandInfo's ContainerInfo image being set to a docker image (ie: docker://busybox)

The docker container will automatically be launched with the specified docker image and the command in the CommandInfo will be passed to docker run.

We're planning as a next step to support options to be passed to docker run and will like to know what docker run options are to be supported while we do the integration.

Please feel free to look at the commits and code changes and provide any feedback as well.