Cert checking now works correctly in both "SSLVerifyClient required" and "SSLVerifyClient optional" (authenticators do safety check themselves)

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

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)

 * Server is now in line with Idea spec concerning client names - they are stored in db and compared lowercase
 * Fixed duplicity check when adding/modifying client
 * Secret is not secret anyway, simplify Client and logging code