closes #1179 (#1199)

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

 
 public class TitleBarLeftButtonParams extends TitleBarButtonParams {
     @Nullable public MaterialMenuDrawable.IconState iconState;
-    public boolean overrideBackPressInJs;
 
     public TitleBarLeftButtonParams(TitleBarButtonParams params) {
         icon = params.icon;
         return eventId.equals("back");
     }
 
-    public boolean hasIcon() {
+    public boolean hasDefaultIcon() {
         return iconState != null;
     }
 
-    public void setOverrideBackPressInJs(boolean overrideBackPressInJs) {
-        this.overrideBackPressInJs = overrideBackPressInJs;
+    public boolean hasCustomIcon() {
+        return icon != null;
     }
 }

android/app/src/main/java/com/reactnativenavigation/views/LeftButton.java

 import com.reactnativenavigation.NavigationApplication;
 import com.reactnativenavigation.params.TitleBarButtonParams;
 import com.reactnativenavigation.params.TitleBarLeftButtonParams;
+import com.reactnativenavigation.utils.ViewUtils;
 
 class LeftButton extends MaterialMenuDrawable implements View.OnClickListener {
 
 
     private void setInitialState() {
         if (params != null) {
-            setIconState(params.iconState);
+            if (params.iconState != null) {
+                setIconState(params.iconState);
+            }
         } else {
             setVisible(false);
         }
     }
 
+    @Override
+    public void setColor(int color) {
+        if (params.hasDefaultIcon()) {
+            super.setColor(color);
+        } else {
+            ViewUtils.tintDrawable(params.icon, color, true );
+        }
+    }
+
     private boolean isBackButton() {
-        return getIconState() == IconState.ARROW;
+        return params.hasDefaultIcon() && getIconState() == IconState.ARROW;
     }
 
     private boolean isSideMenuButton() {
-        return getIconState() == IconState.BURGER;
+        return params.hasDefaultIcon() && getIconState() == IconState.BURGER;
     }
 
     private void sendClickEvent() {

android/app/src/main/java/com/reactnativenavigation/views/TitleBar.java

         if (shouldSetLeftButton(leftButtonParams)) {
             createAndSetLeftButton(leftButtonParams, leftButtonOnClickListener, navigatorEventId, overrideBackPressInJs);
         } else if (hasLeftButton()) {
-            if (leftButtonParams.hasIcon()) {
+            if (leftButtonParams.hasDefaultIcon()) {
                 updateLeftButton(leftButtonParams);
             } else {
                 removeLeftButton();
     }
 
     private boolean shouldSetLeftButton(TitleBarLeftButtonParams leftButtonParams) {
-        return leftButton == null && leftButtonParams != null && leftButtonParams.iconState != null;
+        return leftButton == null && leftButtonParams != null && (leftButtonParams.hasDefaultIcon() || leftButtonParams.hasCustomIcon());
     }
 
     private void createAndSetLeftButton(TitleBarLeftButtonParams leftButtonParams,