TabBarIOS tintColor

Summary:
[Origin Pull request](facebook#961) from [cmcewen](https://github.com/cmcewen)

All the work have been done by @cmcewen, I just rebased his work with the master.
Closes facebook#1337
Github Author: Stan Chollet <stanislas.chollet@gmail.com>

Test Plan: Imported from GitHub, without a `Test Plan:` line.

Examples/UIExplorer/TabBarIOSExample.js

@@ -48,7 +48,9 @@ var TabBarExample = React.createClass({
 
   render: function() {
     return (
-      <TabBarIOS>
+      <TabBarIOS
+        tintColor="black"
+        barTintColor="#3abeff'">
         <TabBarIOS.Item
           title="Blue Tab"
           selected={this.state.selectedTab === 'blueTab'}

Libraries/Components/TabBarIOS/TabBarIOS.ios.js

@@ -25,11 +25,22 @@ var TabBarIOS = React.createClass({
 
   propTypes: {
     style: View.propTypes.style,
+    /**
+     * Color of the currently selected tab icon
+     */
+    tintColor: React.PropTypes.string,
+    /**
+     * Background color of the tab bar
+     */
+    barTintColor: React.PropTypes.string
   },
 
   render: function() {
     return (
-      <RCTTabBar style={[styles.tabGroup, this.props.style]}>
+      <RCTTabBar
+        style={[styles.tabGroup, this.props.style]}
+        tintColor={this.props.tintColor}
+        barTintColor={this.props.barTintColor}>
         {this.props.children}
       </RCTTabBar>
     );

React/Views/RCTTabBar.h

@@ -13,6 +13,9 @@
 
 @interface RCTTabBar : UIView
 
+@property (nonatomic, strong) UIColor *tintColor;
+@property (nonatomic, strong) UIColor *barTintColor;
+
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher NS_DESIGNATED_INITIALIZER;
 
 @end

React/Views/RCTTabBar.m

@@ -114,6 +114,16 @@ - (void)reactBridgeDidFinishTransaction
   }];
 }
 
+- (void)setBarTintColor:(UIColor *)barTintColor
+{
+  _tabController.tabBar.barTintColor = barTintColor;
+}
+
+- (void)setTintColor:(UIColor *)tintColor
+{
+  _tabController.tabBar.tintColor = tintColor;
+}
+
 #pragma mark - UITabBarControllerDelegate
 
 - (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController

React/Views/RCTTabBarManager.m

@@ -23,4 +23,7 @@ - (UIView *)view
   return [[RCTTabBar alloc] initWithEventDispatcher:_bridge.eventDispatcher];
 }
 
+RCT_EXPORT_VIEW_PROPERTY(tintColor, UIColor)
+RCT_EXPORT_VIEW_PROPERTY(barTintColor, UIColor)
+
 @end