添加依赖库 raf

Author: 李钿

package.json

@@ -52,6 +52,7 @@
     "react": "^15.5.4",
     "react-dom": "^15.5.4",
     "react-hot-loader": "^3.0.0-beta.7",
-    "react-motion": "^0.5.0"
+    "react-motion": "^0.5.0",
+    "raf": "^3.1.0"
   }
 }