Offer explanation to new users

[moschlar]

If a new user (with an unknown hostmask) connects from qwebirc, the bot shall offer them a quick explanation of irc, the channels etc via private msg.
Should work like this:
Bot> Hello , I'm , I am a bot on this server. If you're new here I can give you a quick explanation about this chat-system, the people in there and how you can be most successful at receiving help.