http: do not silent HttpRequestDeleted in reply_error(), instead don't call it at all if the request was deleted

- rename first_delay to min_delay; set it to 0.01
- add max_delay which limits the maximum sleep time; set it to 1

--HG--
rename : greentest/test_server.py => greentest/test__server.py

wsgi.WSGIServer: rename socket_or_address parameter to listener; use explicit arguments instead of **kwargs