Close Modal on back press

android/app/src/main/java/com/reactnativenavigation/modal/RnnModal.java

 
     @Override
     public void onBackPressed() {
-        pop();
+        if (mScreenStack.getStackSize() == 1) {
+            super.onBackPressed();
+        } else {
+            pop();
+        }
     }
 
     @Override