Forward the topic authors, handle the author from 333 messages

fix #2

src/irc/irc_client.hpp

@@ -198,6 +198,10 @@ public:
    * Save the topic in the IrcChannel
    */
   void on_topic_received(const IrcMessage& message);
+  /**
+   * Save the topic author in the IrcChannel
+   */
+  void on_topic_who_time_received(const IrcMessage& message);
   /**
    * Empty the topic
    */