refactor Use and Defs element with native code support(iOS)

Example/examples.js

@@ -14,24 +14,9 @@ import * as Symbol from './examples/Symbol';
 import * as Gradients from './examples/Gradients';
 import * as Clipping from './examples/Clipping';
 import * as Image from './examples/Image';
+import * as Definations from './examples/Definations';
 import * as TouchEvents from './examples/TouchEvents';
 
 export {
-    Svg,
-    Rect,
-    Circle,
-    Ellipse,
-    Line,
-    Polygon,
-    Polyline,
-    Path,
-    Text,
-    Stroking,
-    G,
-    Use,
-    Symbol,
-    Gradients,
-    Clipping,
-    Image,
-    TouchEvents
+    Definations
 };