code: public Tag use(String className, String tagBundleName, String tagBundleVersion, Identification id) throws PageException {
  	Queue<Tag> queue = getQueue(toId(className, tagBundleName, tagBundleVersion));
  	Tag tag = queue.poll();
  	if (tag != null) return tag;
  	return loadTag(className, tagBundleName, tagBundleVersion, id);
      }
docs: return a tag to use from a class
  
  @param tagClass
  @return Tag
  @throws PageException