Add iterator accessor

Move iterators to results class

include/valijson/validation_results.hpp

@@ -50,6 +50,22 @@ public:
         std::string description;
     };
 
+    /**
+     * @brief  Return begin iterator for results in the queue.
+     */
+    std::deque<Error>::const_iterator begin() const
+    {
+        return errors.begin();
+    }
+
+    /**
+     * @brief  Return end iterator for results in the queue.
+     */
+    std::deque<Error>::const_iterator end() const
+    {
+        return errors.end();
+    }
+
     /**
      * @brief  Return the number of errors in the queue.
      */