- Replace martian with something simpler.

- Decide about creating a "real" request object during testing.setUp
  vs. creating a dummy request.

- Finish "configuration" documentation chapter and audit the rest of
  the docs for "view configuration" and "route configuration"
  references, etc.  Add one more view registration (and maybe some
  other registration) in the narrative.

- Finish Configurator API documentation.

- notfound/forbidden as Configurator API arguments (get rid of
  set_notfound_view and set_forbidden_view?)