Using application icon if res://icon fails [fixes #920]

src/android/notification/Options.java

@@ -273,6 +273,10 @@ public class Options {
             resId = assets.getResId(DEFAULT_ICON);
         }
 
+        if (resId == 0) {
+            resId = context.getApplicationInfo().icon;
+        }
+
         if (resId == 0) {
             resId = android.R.drawable.ic_popup_reminder;
         }