Fix crash on iOS when reloading page from remote Safari

This closes #110

src/ios/CDVSplashScreen.m

@@ -142,8 +142,16 @@
     _curImageName = nil;
 
     self.viewController.view.userInteractionEnabled = YES;  // re-enable user interaction upon completion
+    @try {
         [self.viewController.view removeObserver:self forKeyPath:@"frame"];
         [self.viewController.view removeObserver:self forKeyPath:@"bounds"];
+    }
+    @catch (NSException *exception) {
+        // When reloading the page from a remotely connected Safari, there
+        // are no observers, so the removeObserver method throws an exception,
+        // that we can safely ignore.
+        // Alternatively we can check whether there are observers before calling removeObserver
+    }
 }
 
 - (CDV_iOSDevice) getCurrentDevice