Use etcd compare and swap to update the list of pods, to remove a race.
Merge pull request #265 from brendandburns/cas

Use etcd compare and swap to update the list of pods, to remove a race.
Add a link to the update demo.
Cleaning up container ID handling inside kubelet
Introduce a type for docker container ids
DockerContaineId->DockerId
Merge pull request #254 from jjhuff/container_id

Cleaning up container ID handling inside kubelet