Update guestbook-go.

IP-per-service compatible.  Uses kubectl.
Don't accept empty input in DecodeInto
Fix dangerous Sprintf
Merge pull request #1848 from lavalamp/fix2

Fix dangerous Sprintf
Merge pull request #1844 from lavalamp/fix

Don't accept empty input in DecodeInto
Fix etcd in proxy for namespace awareness
Read BoundPods from etcd instead of ContainerManifestList

There are three values that uniquely identify a pod on a host -
the configuration source (etcd, file, http), the pod name, and the
pod namespace. This change ensures that configuration properly
makes those names unique by changing podFullName to contain both
name (currently ID in v1beta1, Name in v1beta3) and namespace.

The Kubelet does not properly handle information requests for
pods not in the default namespace at this time.
Write BoundPods to etcd instead of ContainerManifestList

Rename ManifestFactory -> BoundPodFactory and change the general structure
of the call to focus on BoundPod.
Rename the etcd path for pods to be /registry/nodes/<>/boundpods
Merge pull request #1850 from thockin/nsinteg

Fix etcd in proxy for namespace awareness
Merge pull request #1840 from eparis/bind_pods

Bind pods
Merge pull request #1828 from thockin/guestbook

Update guestbook-go.
Add basic authorization.

Added basic interface for authorizer implementations.
Added default "authorize everything" implementation.
Added authorization checks in each REST handler routine.
Added tests that these routines return forbidden error code
when the authorizer implementation denies access.