Rename JSONBase -> TypeMeta in preparation for v1beta3

Will make subsequent refactor much easier

pkg/master/pod_cache_test.go

@@ -92,7 +92,7 @@ func TestPodGetPodInfoGetter(t *testing.T) {
 
 func TestPodUpdateAllContainers(t *testing.T) {
 	pod := api.Pod{
-		JSONBase: api.JSONBase{ID: "foo"},
+		TypeMeta: api.TypeMeta{ID: "foo"},
 		CurrentState: api.PodState{
 			Host: "machine",
 		},