- Add a ``pyramid.url.route_path`` API, allowing folks to generate relative
  URLs.  Calling ``route_path`` is the same as calling
  ``pyramid.url.route_url`` with the argument ``_app_url`` equal to the empty
  string.

- Add a ``pyramid.request.Request.route_path`` API.  This is a convenience
  method of the request which calls ``pyramid.url.route_url``.