irclagtimer.h: signals -> Q_SIGNALS
Make IrcBufferModel::create() QML compatible

IrcBufferModel {
    id: model
    function create(title) {
        if (connection.network.isChannel(title))
            return channelComponent.createObject(model)
        return bufferComponent.createObject(model)
    }
}
Split IrcBufferModel::create() -> createBuffer() & createChannel()
IrcConnection::createCtcpReply() - add support for SOURCE & CLIENTINFO