* `tornado.web.RequestHandler.set_header` now properly sanitizes input
  values to protect against header injection, response splitting, etc.
  (it has always attempted to do this, but the check was incorrect).
  Note that redirects, the most likely source of such bugs, are protected
  by a separate check in `.RequestHandler.redirect`.

Bug fixes
~~~~~~~~~

* Colored logging configuration in `tornado.options` is compatible with
  Python 3.2.3 (and 3.3).