Use "$this->response->body($foo)" instead of "print $foo" in controllers (100 places).
Remove "print" from a few views, too.
Put reponse-related JSON::reply() and Ajax::response() in Response class override.
- move the functions to the class override.
- revise the direct header and print calls in the functions to Response methods.
- add optional flag to json method to use text/plain (iframe compat - see #2022).
- use optional flag in Controller_Admin_Watermarks to clean up json calls.
- change 78 JSON::reply calls to response->json.
- change 3 Ajax::response calls to response->ajax.
- remove JSON and Ajax helpers.
Revise rest controller to send Response object to Rest::reply().
This gives Rest::reply() the ability to use the Response methods.
Merge pull request #300 from shadlaws/response_update

Response updates.