Set the default nick (pre-registration) to '*' instead of null
Set the default nick (pre-registration) to '*' instead of null

Some errors such as "You must authenticate" were being sent with the
wrong number of parameters because the nick was empty.

'*' is used as a placeholder for the nick before the connection
registration is done, as commonly seen in the initial NOTICE sent
from some servers.

gitterHQ/irc-bridge,gitterHQ/irc-bridge