Merge branch 'master' of https://github.com/kubernetes/kubernetes.github.io into release-1.7

* 'master' of https://github.com/kubernetes/kubernetes.github.io:
  whatisk8s - Chinese version (#3243)
  split rows and nest to stack columns (#4129)
  Updates to docs/admin/kubelet-tls-bootstrapping (#3617)
  Replace "Pod Injection Policy" with "Pod Preset" (#3667)
  Change example PersistentVolumeClaim
  add PodNodeSelector to admission-controllers (#3691)
  Get pods using a label selector instead of hardcoded indexes. Use JsonPath instead of go-template.
  correct_init_container_state (#3972)
  kubernetes.github.io/docs/tasks/administer-cluster: operating etcd clusters
  Remove --no-check-certificate flag in bare_metal_offline.md

docs/tasks/inject-data-application/podpreset.md

@@ -74,7 +74,7 @@ of the form: `podpreset.admission.kubernetes.io/exclude: "true"`.
 ### Simple Pod Spec Example
 
 This is a simple example to show how a Pod spec is modified by the Pod
-Injection Policy.
+Preset.
 
 **User submitted pod spec:**
 
@@ -148,8 +148,8 @@ spec:
 
 ### Pod Spec with `ConfigMap` Example
 
-This is an example to show how a Pod spec is modified by the Pod Injection
-Policy that defines a `ConfigMap` for Environment Variables.
+This is an example to show how a Pod spec is modified by the Pod Preset 
+that defines a `ConfigMap` for Environment Variables.
 
 **User submitted pod spec:**
 
@@ -266,7 +266,7 @@ spec:
 ### ReplicaSet with Pod Spec Example
 
 The following example shows that only the pod spec is modified by the Pod
-Injection Policy.
+Preset.
 
 **User submitted ReplicaSet:**
 
@@ -460,8 +460,8 @@ spec:
 
 ### Conflict Example
 
-This is a example to show how a Pod spec is not modified by the Pod Injection
-Policy when there is a conflict.
+This is an example to show how a Pod spec is not modified by the Pod Preset 
+when there is a conflict.
 
 **User submitted pod spec:**