* only when using http01, only match default_server by port
* import errors
* put back in the code that creates a dummy block, but only when we can't find anything else
* get http01 challenge working
* support multiple challenge types in configurator.py
* update existing nginx tests
* lint
* refactor NginxHttp01 and NginxTlsSni01 to both now inherit from NginxChallengePerformer
* remove TODO
* challenges_test tests with both tlssni01 and http01
* Make challenges.py more abstract to make lint happier
* add pylint disables to the tests to make pylint happier about the inheritance and abstraction situation
* no need to cover raise NotImplementedError() lines
* python3 compatibility
* test that http01 perform is called
* only remove ssl from addresses during http01
* Initialize addrs_to_add
* Change Nginx http01 to modify server block so the site doesn't stop serving while getting a cert
* pass existing unit tests
* rename sni --> http01 in unit tests
* lint
* fix configurator test
* select an http block instead of https
* properly test for port number
* use domains that have matching addresses
* remove debugger
* remove access_log and error_log cruft that wasn't being executed
* continue to return None from choose_redirect_vhost when create_if_no_match is False
* add nginx integration test
