The roster list is now split from MainWindow into RosterWindow, which
can be used arbitrarily for selecting something from contacts. The
im_what, title, and target can be specified.
Right now it's in use under the Chat menu, "New chat…". Chats can only
have two members (DM/PM), so "New chat…" directly leads to the roster
list.
In the future, roster list might be extended to allow specification of
non-contact users based on their identifiers, or filtering based on
protocol/account― this could help it with "invites" to future rooms,
etc.
IM_CREATE_CHAT and IM_CHAT_CREATED were also added to the protocol API,
allowing a new chat to be explicitly created from Caya or the protocol.
Also adds a function to protocols to toggle this― if CayaProtocol::SaveLogs()
returns true, then local logs will be used to popualte conversation
windows. Otherwise, it's up to the protocol itself.
A new protocol IM_MESSAGE was also created, IM_LOGS_RECEIVED, which can
be used to populate conversations with old logs.
* Shows notifications when contacts go online or offline. Unfortunately XMPP plugins will send presence notifications when the roster is populate so presence notification is shown for every online contact when the roster list view is populated the first time.