[Improvement] Support Vue.use to register a component (#401)

packages/toast/toast.vue

@@ -19,19 +19,13 @@
 </template>
 
 <script>
-import Icon from '../icon';
-import Loading from '../loading';
+import { create } from '../utils';
 
 const DEFAULT_STYLE_LIST = ['success', 'fail', 'loading'];
 
-export default {
+export default create({
   name: 'van-toast',
 
-  components: {
-    Icon,
-    Loading
-  },
-
   props: {
     mask: Boolean,
     message: [String, Number],
@@ -57,5 +51,5 @@ export default {
       return DEFAULT_STYLE_LIST.indexOf(this.type) !== -1 ? 'default' : this.type;
     }
   }
-};
+});
 </script>