Conflict resolution.
Significant cleanup.
- RestDTO and RestDTOList are completely redundant.  You can easily make a DTO class by simply defining an iterator or making the serailizable fields public; the REST output logic now works by simply enumerating the object's fields using foreach().  This also means that the json.php stuff is totally unecessary.  Just pass an array of DTOs to the built-in json_encode PHP function.
- Renamed rest_utils.php to rest_emitter.php, which better describes what it does.
- Renamed xml.php to xml_encoder.php, which matches the class name.
- Prefer instance methods to static methods, even on utility classes; better modularity.