Add disabledColor property to TitleBar buttons

Can also be set cross app by using titleBarDisabledButtonColor property in appStyle

android/app/src/main/java/com/reactnativenavigation/params/StyleParams.java

             return color != null;
         }
 
+        @ColorInt
         public int getColor() {
             if (!hasColor()) {
                 throw new RuntimeException("Color undefined");
     public boolean titleBarHidden;
     public Color titleBarTitleColor;
     public Color titleBarButtonColor;
+    public Color titleBarDisabledButtonColor;
     public boolean backButtonHidden;
 
     public Color topTabTextColor;

android/app/src/main/java/com/reactnativenavigation/params/TitleBarButtonParams.java

     public String label;
     public Drawable icon;
     public StyleParams.Color color;
+    public StyleParams.Color disabledColor;
     public ShowAsAction showAsAction;
     public boolean enabled = true;
 

android/app/src/main/java/com/reactnativenavigation/params/parsers/StyleParamsParser.java

 package com.reactnativenavigation.params.parsers;
 
+import android.graphics.Color;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
         result.titleBarHidden = getBoolean("titleBarHidden", getDefaultTopBarHidden());
         result.titleBarTitleColor = getColor("titleBarTitleColor", getDefaultTitleBarColor());
         result.titleBarButtonColor = getColor("titleBarButtonColor", getTitleBarButtonColor());
+        result.titleBarDisabledButtonColor = getColor("titleBarDisabledButtonColor", getTitleBarDisabledButtonColor());
         result.backButtonHidden = getBoolean("backButtonHidden", getDefaultBackButtonHidden());
         result.topTabsHidden = getBoolean("topTabsHidden", getDefaultTopTabsHidden());
 
 
         result.bottomTabsHidden = getBoolean("bottomTabsHidden", getDefaultBottomTabsHidden());
         result.drawScreenAboveBottomTabs = !result.bottomTabsHidden &&
-                params.getBoolean("drawScreenAboveBottomTabs", getDefaultDrawScreenAboveBottomTabs());
+                                           params.getBoolean("drawScreenAboveBottomTabs", getDefaultDrawScreenAboveBottomTabs());
         result.bottomTabsHiddenOnScroll =
                 getBoolean("bottomTabsHiddenOnScroll", getDefaultBottomTabsHiddenOnScroll());
         result.bottomTabsColor = getColor("bottomTabsColor", getDefaultBottomTabsColor());
         return AppStyle.appStyle == null ? new StyleParams.Color() : AppStyle.appStyle.titleBarButtonColor;
     }
 
+    @Nullable
+    private StyleParams.Color getTitleBarDisabledButtonColor() {
+        return AppStyle.appStyle == null ? new StyleParams.Color(Color.LTGRAY) : AppStyle.appStyle.titleBarDisabledButtonColor;
+    }
+
     private boolean getDefaultTopBarHidden() {
         return AppStyle.appStyle != null && AppStyle.appStyle.titleBarHidden;
     }

android/app/src/main/java/com/reactnativenavigation/params/parsers/TitleBarButtonParamsParser.java

         if (hasKey(bundle,"icon")) {
             result.icon = ImageLoader.loadImage(bundle.getString("icon"));
         }
-        result.color = getColor(bundle, AppStyle.appStyle.titleBarButtonColor);
+        result.color = getColor(bundle, "color", AppStyle.appStyle.titleBarButtonColor);
+        result.disabledColor = getColor(bundle, "disabledColor", AppStyle.appStyle.titleBarDisabledButtonColor);
         result.showAsAction = parseShowAsAction(bundle.getString("showAsAction"));
         result.enabled = bundle.getBoolean("enabled", true);
         result.eventId = bundle.getString("id");
         return result;
     }
 
-    private StyleParams.Color getColor(Bundle bundle, StyleParams.Color defaultColor) {
-        StyleParams.Color color = StyleParams.Color.parse(bundle.getString("color"));
+    private StyleParams.Color getColor(Bundle bundle, String key, StyleParams.Color defaultColor) {
+        StyleParams.Color color = StyleParams.Color.parse(bundle.getString(key));
         return color.hasColor() || defaultColor == null ? color : defaultColor;
     }
 

android/app/src/main/java/com/reactnativenavigation/utils/ViewUtils.java

 package com.reactnativenavigation.utils;
 
 import android.content.Context;
-import android.graphics.Color;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffColorFilter;
 import android.graphics.drawable.Drawable;
 import android.view.WindowManager;
 
 import com.reactnativenavigation.NavigationApplication;
+import com.reactnativenavigation.params.AppStyle;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
     }
 
     public static void tintDrawable(Drawable drawable, int tint, boolean enabled) {
-        drawable.setColorFilter(new PorterDuffColorFilter(enabled ? tint : Color.LTGRAY, PorterDuff.Mode.SRC_IN));
+        drawable.setColorFilter(new PorterDuffColorFilter(enabled ? tint :
+                AppStyle.appStyle.titleBarDisabledButtonColor.getColor(),
+                PorterDuff.Mode.SRC_IN));
     }
 
     public static float convertDpToPixel(float dp) {