customize tab badge color (#1932)

docs/screen-api.md

 ```js
 this.props.navigator.setTabBadge({
   tabIndex: 0, // (optional) if missing, the badge will be added to this screen's tab
-  badge: 17 // badge value, null to remove badge
+  badge: 17, // badge value, null to remove badge
+  badgeColor: '#006400', // (optional) if missing, the badge will use the default color
 });
 ```
 ## setTabButton(params = {})

ios/RCCTabBarController.m

       }
       else
       {
+        NSString *badgeColor = actionParams[@"badgeColor"];
+        UIColor *color = badgeColor != (id)[NSNull null] ? [RCTConvert UIColor:badgeColor] : nil;
+        viewController.tabBarItem.badgeColor = color;
         viewController.tabBarItem.badgeValue = [NSString stringWithFormat:@"%@", badge];
       }
     }

src/deprecated/controllers/index.js

         return RCCManager.TabBarControllerIOS(id, "setTabBarHidden", params);
       },
       setBadge: function (params) {
+        _processProperties(params);
         return RCCManager.TabBarControllerIOS(id, "setBadge", params);
       },
       switchTo: function (params) {

src/deprecated/platformSpecificDeprecated.ios.js

   if (params.tabIndex || params.tabIndex === 0) {
     Controllers.TabBarControllerIOS(controllerID + '_tabs').setBadge({
       tabIndex: params.tabIndex,
-      badge: params.badge
+      badge: params.badge,
+      badgeColor: params.badgeColor
     });
   } else {
     Controllers.TabBarControllerIOS(controllerID + '_tabs').setBadge({