when the app is rotated, reload the root view.

Fixes facebook#813

Author: siuying

React/Base/RCTRootView.m

@@ -109,6 +109,10 @@ - (void)setUp
                                              selector:@selector(reload)
                                                  name:RCTReloadViewsNotification
                                                object:_bridge];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(reload)
+                                                 name:UIDeviceOrientationDidChangeNotification
+                                               object:nil];
     if (_bridge.loaded) {
       [self bundleFinishedLoading];
     } else {