Fixes topBar.backButton.color - #4164

lib/ios/RNNNavigationControllerPresenter.m

 	[navigationController rnn_setNavigationBarLargeTitleVisible:[options.topBar.largeTitle.visible getWithDefaultValue:NO]];
 	[navigationController rnn_setNavigationBarLargeTitleFontFamily:[options.topBar.largeTitle.fontFamily getWithDefaultValue:nil] fontSize:[options.topBar.largeTitle.fontSize getWithDefaultValue:nil] color:[options.topBar.largeTitle.color getWithDefaultValue:nil]];
 	[navigationController rnn_setNavigationBarFontFamily:[options.topBar.title.fontFamily getWithDefaultValue:nil] fontSize:[options.topBar.title.fontSize getWithDefaultValue:nil] color:[options.topBar.title.color getWithDefaultValue:nil]];
+	[navigationController rnn_setBackButtonColor:[options.topBar.backButton.color getWithDefaultValue:nil]];
 }
 
 - (void)applyOptionsOnWillMoveToParentViewController:(RNNNavigationOptions *)options {
 		
 	}
 	
+	if (options.topBar.backButton.color.hasValue) {
+		[navigationController rnn_setBackButtonColor:options.topBar.backButton.color.get];
+	}
+	
 	[navigationController rnn_setNavigationBarLargeTitleFontFamily:[withDefault.topBar.largeTitle.fontFamily getWithDefaultValue:nil] fontSize:[withDefault.topBar.largeTitle.fontSize getWithDefaultValue:nil] color:[withDefault.topBar.largeTitle.color getWithDefaultValue:nil]];
 	
 	[navigationController rnn_setNavigationBarFontFamily:[withDefault.topBar.title.fontFamily getWithDefaultValue:nil] fontSize:[withDefault.topBar.title.fontSize getWithDefaultValue:nil] color:[withDefault.topBar.title.color getWithDefaultValue:nil]];

lib/ios/ReactNativeNavigationTests/RNNNavigationControllerPresenterTest.m

 	[_bindedViewController verify];
 }
 
+- (void)testApplyOptions_shouldSetBackButtonColor_withDefaultValues {
+	[[_bindedViewController expect] rnn_setBackButtonColor:nil];
+	[self.uut applyOptions:self.options];
+	[_bindedViewController verify];
+}
+
+- (void)testApplyOptions_shouldSetBackButtonColor_withColor {
+	self.options.topBar.backButton.color = [[Color alloc] initWithValue:[UIColor redColor]];
+	[[_bindedViewController expect] rnn_setBackButtonColor:[UIColor redColor]];
+	[self.uut applyOptions:self.options];
+	[_bindedViewController verify];
+}
+
 - (void)testApplyOptionsOnWillMoveToParent_shouldSetBackButtonOnBindedViewController_withIcon {
     Image* image = [[Image alloc] initWithValue:[UIImage new]];
     self.options.topBar.backButton.icon = image;

lib/ios/UINavigationController+RNNOptions.h

 
 - (void)rnn_setNavigationBarLargeTitleFontFamily:(NSString *)fontFamily fontSize:(NSNumber *)fontSize color:(UIColor *)color;
 
+- (void)rnn_setBackButtonColor:(UIColor *)color;
+
 @end

lib/ios/UINavigationController+RNNOptions.m

 	
 	backItem.title = title ? title : lastViewControllerInStack.navigationItem.title;
 	backItem.tintColor = color;
-	
+
 	lastViewControllerInStack.navigationItem.backBarButtonItem = backItem;
 }
 
+- (void)rnn_setBackButtonColor:(UIColor *)color {
+	self.navigationBar.tintColor = color;
+}
+
 - (void)rnn_setNavigationBarClipsToBounds:(BOOL)clipsToBounds {
 	self.navigationBar.clipsToBounds = clipsToBounds;
 }