Understand OOMKilled reason from 'docker inspect'

All dependencies are resolved, and here are the code to pick up OOMKilled and Error information from docker 1.4. 

closed  #2834

cc/ @vishh 

I created a container for oom_test, here is the related status from kubelet:

            "oom-test": {
                "state": {
                    "termination": {
                        "exitCode": 137,
                        "reason": "OOM Killed",
                        "startedAt": "2014-12-18T23:22:25Z",
                        "finishedAt": "2014-12-18T23:22:26Z"
                    }
                },