Added support for IPv6 addresses in DNS.

include/ipv6_address.h

@@ -72,6 +72,15 @@ public:
      */
     IPv6Address(const std::string &addr);
     
+    /**
+     * \brief Constructor from a buffer.
+     * 
+     * The ptr parameter must be at least address_size bytes long.
+     * 
+     * \param ptr The buffer from which to construct this object.
+     */
+    IPv6Address(const_iterator ptr);
+    
     /**
      * \brief Retrieve the string representation of this address.
      *