function addToCache(audios) {
   if (!(audios instanceof Array)) {
      audios = [audios];
   }

   var docLoc = document.location.href;
   audios.forEach(function(audio) {
      CACHE[audio.gamejsKey] = audio;
   });
   return;
}
@param {dom.ImgElement} audios the <audio> elements to put into cache
@ignore