Rename JSONBase -> TypeMeta in preparation for v1beta3

Will make subsequent refactor much easier

pkg/watch/json/decoder_test.go

@@ -33,7 +33,7 @@ func TestDecoder(t *testing.T) {
 	out, in := io.Pipe()
 	decoder := NewDecoder(out, v1beta1.Codec)
 
-	expect := &api.Pod{JSONBase: api.JSONBase{ID: "foo"}}
+	expect := &api.Pod{TypeMeta: api.TypeMeta{ID: "foo"}}
 	encoder := json.NewEncoder(in)
 	go func() {
 		data, err := v1beta1.Codec.Encode(expect)