Move Image.resizeMode to component

Summary:
Using resizeMode on Image component returns a warning, it needs to be passed by param
Closes https://github.com/facebook/react-native/pull/4791

Reviewed By: svcscm

Differential Revision: D2767093

Pulled By: spicyj

fb-gh-sync-id: 5ab6a2e949d4c68244b5e890a429aaf1f15118a9

Examples/UIExplorer/ImageCapInsetsExample.js

@@ -35,6 +35,7 @@ var ImageCapInsetsExample = React.createClass({
           <Image
             source={require('image!story-background')}
             style={styles.storyBackground}
+            resizeMode={Image.resizeMode.stretch}
             capInsets={{left: 0, right: 0, bottom: 0, top: 0}}
           />
         </View>
@@ -66,7 +67,6 @@ var styles = StyleSheet.create({
     width: 250,
     height: 150,
     borderWidth: 1,
-    resizeMode: Image.resizeMode.stretch,
   },
   text: {
     fontSize: 13.5,