fix custom nav bar view and add initial props (#1172)

example/src/screens/CustomNavBar.js

     return (
       <View style={styles.container}>
         <TouchableOpacity stye={styles.button} onPress={ () => alert('Thanks for that :)') }>
-          <Text style={{color: 'red', textAlign: 'center'}}>Hi Custom</Text>
+          <Text style={{color: 'red', textAlign: 'center'}}>{this.props.name}</Text>
           <Text style={{textAlign: 'center'}}>Press Me</Text>
         </TouchableOpacity>
 

example/src/screens/CustomNavBarScreen.js

 export default class CustomNavBarScreen extends Component {
   static navigatorStyle = {
     drawUnderTabBar: true,
-    navBarCustomView: 'example.CustomNavBar'
+    navBarCustomView: 'example.CustomNavBar',
+    navBarCustomViewInitialProps: {name: 'Hi Custom'}
   };
 
 

ios/RCCViewController.m

   }
   
   NSString *navBarCustomView = self.navigatorStyle[@"navBarCustomView"];
-  if (navBarCustomView && !self.navigationItem.titleView) {
+  if (navBarCustomView && ![self.navigationItem.titleView isKindOfClass:[RCCCustomTitleView class]]) {
     if ([self.view isKindOfClass:[RCTRootView class]]) {
       
       RCTBridge *bridge = ((RCTRootView*)self.view).bridge;
-      RCTRootView *reactView = [[RCTRootView alloc] initWithBridge:bridge moduleName:navBarCustomView initialProperties:nil];
+      
+      NSDictionary *initialProps = self.navigatorStyle[@"navBarCustomViewInitialProps"];
+      RCTRootView *reactView = [[RCTRootView alloc] initWithBridge:bridge moduleName:navBarCustomView initialProperties:initialProps];
       
       RCCCustomTitleView *titleView = [[RCCCustomTitleView alloc] initWithFrame:self.navigationController.navigationBar.bounds subView:reactView alignment:self.navigatorStyle[@"navBarComponentAlignment"]];
       titleView.backgroundColor = [UIColor clearColor];
       reactView.backgroundColor = [UIColor clearColor];
-    
+      
       self.navigationItem.titleView = titleView;
       
       self.navigationItem.titleView.backgroundColor = [UIColor clearColor];
       self.navigationItem.titleView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin;
       self.navigationItem.titleView.clipsToBounds = YES;
     }
-  }  
+  }
 }