Fixed undefined offset case for OneOffArray.

Author: Sevavietl

README.md

@@ -162,7 +162,7 @@ Compared to `CompositeKeyArray`, `XPathKeyArray` has some limitations:
 
 ## Dotted Key Array
 
-**This is not a real xpath!** This class instead of array-like key users string of keys delimited with `/`.
+This class instead of array-like key users string of keys delimited with `.`.
 
 ```php
     $array = new DottedKeyArray([

src/OneOffArray.php

@@ -6,7 +6,7 @@ class OneOffArray extends BaseArray
 {
     public function offsetGet($offset)
     {
-        $value = $this->container[$offset];
+        $value = parent::offsetGet($offset);
         unset($this->container[$offset]);
 
         return $value;