introduce new say_string method of doing say and use it in mod_say_en as an example...

introduce new say_string method of doing say and use it in mod_say_en as an example.  try: eval ${say_string en.gsm en current_date_time pronounced ${strepoch()}} from the cli with this patch.  We can do more to centralize the say things and go back and apply it to other langs, using this method you can set the desired file ext as well which I think is a bounty....