Support to exclude some sender nicks for notifications

[bigpresh]

I think it would be very useful to be able to blacklist nick-highlight notifications from certain nicks (and perhaps a similar option to instead accept highlights only from a specified list - but blacklisting would be more generally useful I think).

Use-case: sitting in a channel with a bot that announces the list of players in a game - if I'm in-game, every time the list is announced I'd get an alert from YAAIC. It would be nice to be able to tell YAAIC to ignore nick highlights from the bot's nick.

Even more powerful would be the ability to use partial patterns, e.g. *bot.