Add twitch-specific functionality

[Twitch-Plays-Pokemon]

Parse Twitch-specific message metadata.

Twitch includes information such as color, name with capitalization and emote information alongside messages in a (AFAICT) non-standard way.

[moshmage]

This is a server-specific problem, not a RFC/Library specific problem. I don't see how everyone would benefit from this.

You're telling us that you need to do a client.send("CAP REQ", "twitch.tv/tags") first so I'm thinking there's a specifc RAW event that the twitch IRC server sends when you ask for CAP REQ, yes? If the latter is true, then you should've simply made a case-check;

I'm thinking different people would like different "twitch tag solvers" for "different reasons" so, I'd go even further and set a configurable option to "should we listen to an array custom RAW events?" and its counter-part callback.

This way it would: a) solve all twitchs problem b) solve everyones' flavour of IRC problem c) be irrelevant to whoever does not need those.

Also, please adhere to the code-syntax (spaces between if and (, single-quotes instead of doubled ones, etc)