Interface Loaded

src/main/java/fieldbox/io/IO.java:917–919

tag interface for boxes, method will be called after all boxes have been loaded (and all properties set). Boxes that throw exceptions won't be loaded after all.

	static public class Document {
		public List<External> externalList;
		public Map<String, Filespec> knownFiles;
		public Set<String> knownProperties;
	}

	static public class External {