support transition animations on root changes

README.md

     right: { // optional, define if you want a drawer from the right
       screen: 'example.SecondSideMenu' // unique ID registered with Navigation.registerScreen
     }
-  }
+  },
+  animationType: 'slide-down' // optional, add transition animation to root change: 'none', 'slide-down', 'fade'
 });
 ```
 
     right: { // optional, define if you want a drawer from the right
       screen: 'example.SecondSideMenu' // unique ID registered with Navigation.registerScreen
     }
-  }
+  },
+  animationType: 'slide-down' // optional, add transition animation to root change: 'none', 'slide-down', 'fade'
 });
 ```
 

example-redux/ios/exampleRedux/AppDelegate.m

   // **********************************************
   self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
   self.window.backgroundColor = [UIColor whiteColor];
-  [[RCCManager sharedIntance] initBridgeWithBundleURL:jsCodeLocation];
+  [[RCCManager sharedInstance] initBridgeWithBundleURL:jsCodeLocation];
   
   /*
    // original RN bootstrap - remove this part

example-redux/src/app.js

               title: 'Screen Two',
               navigatorStyle: {}
             }
-          ]
+          ],
+          animationType: 'slide-down'
         });
         return;
       default:

src/platformSpecific.ios.js

     }
   });
   ControllerRegistry.registerController(controllerID, () => Controller);
-  ControllerRegistry.setRootController(controllerID);
+  ControllerRegistry.setRootController(controllerID, params.animationType);
 }
 
 function startSingleScreenApp(params) {
     }
   });
   ControllerRegistry.registerController(controllerID, () => Controller);
-  ControllerRegistry.setRootController(controllerID);
+  ControllerRegistry.setRootController(controllerID, params.animationType);
 }
 
 function _mergeScreenSpecificSettings(screenID, screenInstanceID, params) {