Convert builder images to go

Builder images converted to go commands. Main builder code in pkg/build/builder
The methods in kubelet/dockertools/config.go are private (https://github.com/openshift/origin/blob/master/Godeps/_workspace/src/github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools/config.go) and publicly they're only accessible in the context of pulling an image (https://github.com/openshift/origin/blob/master/Godeps/_workspace/src/github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools/docker.go#L88)