Channel/Room/PM support

[vineetsk1]

Support different channels/rooms, and private messages.

Currently this will be put on the backlog until Flash/main Eterna chat supports this.

[luxaritas]

I'm doubting Flash chat will be further maintained, but a good possibility for HTML-Chat (might need to move the issue to there). Also could be effected by some of the discussion about community infrastructure improvement (i.e. I have some ideas that could take this idea and expand it farther).