Added combined X509MixMatchAuthenticator, which allows for logging in both clients with hostname cert and with client name cert

- and added poll_time parameter to receiver section in README (which has already existed but was not documented)

Fixed first client's access without id (IndexError: tuple index out of range) (thanks to Radko Krkos)

getEvents - id<=0 now resets server's notion of client's id to last N events (and starts sending there)

Some Python/ssl module versions incorrectly initialize hashlib, causing weird openssl errors. Importing hashlib explicitly helps.

More sensible configuration file defaults, some sections left commented to prevent unnecessary default filtering and/or adding Node info