improved es6 syntax, thanks tautvilas

package.json

     "type": "git",
     "url": "https://github.com/wix/react-native-navigation.git"
   },
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "React Native Navigation - truly native navigation for iOS and Android",
   "nativePackage": true,
   "bugs": {

src/Navigation.js

   return platformSpecific.dismissModal(params);
 }
 
-export default Navigation = {
+export default {
   registerScreen,
   getRegisteredScreen,
   registerComponent,

src/platformSpecific.ios.js

   Modal.dismissController(params.animationType);
 }
 
-export default platformSpecific = {
+export default {
   startTabBasedApp,
   startSingleScreenApp,
   navigatorPush,

src/utils.js

   return (Math.random()*1e20).toString(36);
 }
 
-export default utils = {
+export default {
   getRandomId
 }