Handle case with no available rooms

fixes #181

src/TopRoomBar.cc

@@ -144,6 +144,9 @@ TopRoomBar::TopRoomBar(QWidget *parent)
         menu_->addAction(leaveRoom_);
 
         connect(settingsBtn_, &QPushButton::clicked, this, [=]() {
+                if (roomSettings_.isNull())
+                        return;
+
                 if (roomSettings_->isNotificationsEnabled())
                         toggleNotifications_->setText(tr("Disable notifications"));
                 else

src/timeline/TimelineViewManager.cc

@@ -68,6 +68,9 @@ TimelineViewManager::messageSendFailed(const QString &roomid, int txn_id)
 void
 TimelineViewManager::queueTextMessage(const QString &msg)
 {
+        if (active_room_.isEmpty())
+                return;
+
         auto room_id = active_room_;
         auto view    = views_[room_id];
 
@@ -77,6 +80,9 @@ TimelineViewManager::queueTextMessage(const QString &msg)
 void
 TimelineViewManager::queueEmoteMessage(const QString &msg)
 {
+        if (active_room_.isEmpty())
+                return;
+
         auto room_id = active_room_;
         auto view    = views_[room_id];