This is a commit with it's foot in a lot of places, but:
The Conversation class was created as the abstraction of chats: All
ImMessages that are relevant to a conversation get routed through it,
meta-data on chats is stored in it (even if right now that's basically
limited to the user list and ID).
Server was given more methods to help accessing contacts―
ContactById(BString) and AddContact(Contact*). This better allows
Conversations to add and fetch Contacts as necessary. Right now, all
users in chats are treated as Contacts, so in the future creating an
independent userlist for Server (fUserMap?) would be useful.
Server also now stores all Conversations (fChatMap) and has some
convenience methods like for Contacts: Conversations(),
ConversationById(BString), and AddConversation(Conversation*).
CayaRenderView has been changed to not store user nicks, and will use
the appropriate nick of any arbitrarily-numbered user.
Users also have a map of all Conversations they are a part of
(fChatMap).
The Remove* methods of KeyMap now return the removed item.
This dichotomy is useful and necessary in multi-user chats, so I split
Contact into a parent class, User. User should be used for generic
members of rooms, Contact used mainly with the roster.