Add styles for read/unread messages

[spaceninja]

In most Adium themes, there's a suble design change applie to read/unread messages -- this is especially noticable in group chats, like IRC, where you may click back to the chat window and have 80 or 100 lines or new messages since you last looked. Giving a visual distinction allows you to just scan up the list to the last read message.

I love the work you've done porting the hipchat styles over, and I know this isn't a standard part of hipchat, but it's the one thing that I really miss from Adium themes, and it makes group chats very difficult for me to use.

I'm sorry I don't have more details about what Adium calls this feature, or how it's implimented. If you need, I can provide some screenshots of other themes to illustrate what I'm talking about.