allow kubectl subcmds to process multiple resources

- use resource.Visit() to recursively process resources, as well as, aggregate
errors where possible

hack/testdata/recursive/deployment/deployment/nginx-broken.yaml

@@ -0,0 +1,18 @@
+apiVersion: extensions/v1beta1
+ind: Deployment
+metadata:
+  name: nginx2-deployment
+  labels:
+    app: nginx2-deployment
+spec:
+  replicas: 2
+  template:
+    metadata:
+      labels:
+        app: nginx2
+    spec:
+      containers:
+      - name: nginx
+        image: gcr.io/google-containers/nginx:1.7.9
+        ports:
+        - containerPort: 80

hack/testdata/recursive/deployment/deployment/nginx.yaml

@@ -0,0 +1,18 @@
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: nginx1-deployment
+  labels:
+    app: nginx1-deployment
+spec:
+  replicas: 2
+  template:
+    metadata:
+      labels:
+        app: nginx1
+    spec:
+      containers:
+      - name: nginx
+        image: gcr.io/google-containers/nginx:1.7.9
+        ports:
+        - containerPort: 80

hack/testdata/recursive/deployment/nginx.yaml

@@ -0,0 +1,18 @@
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: nginx0-deployment
+  labels:
+    app: nginx0-deployment
+spec:
+  replicas: 2
+  template:
+    metadata:
+      labels:
+        app: nginx0
+    spec:
+      containers:
+      - name: nginx
+        image: gcr.io/google-containers/nginx:1.7.9
+        ports:
+        - containerPort: 80