Bugs like: * Tab title not matching shown chat window * Duplicated tab titles after tab movement Swift is also subject to QTBUG-36455, which is fixed for Qt >= 5.3.0. This commit removes the use of application wide focus handlers in QtChatWindow class, the QtChatWindow::qAppFocusChanged method. The reason for this is due to the way QTabBar::moveTab is implemented in Qt which we use for the Trellis feature. Internally QTabBar::moveTab first adjusts its tab bar labels, then removes the tab from its old location in the internal QStackedLayout and then inserts it in the new location. After the remove Qt gives focus to another widget via a focus change that does not go through the event loop of the application and is not interceptable with eventFilters. Previously we would set the focus and call other signals in the application wide focus change handler which then used the currently inconsistent QTabBar/QTabWidget. Test-Information: Tested tab switching and movement on Windows 8 (Qt 5.3.2), OS X 10.9.5 (Qt 5.4.3) and Ubuntu 14.04.2 LTS (Qt 5.4.3). Change-Id: Ief423c4add58a90279109f72fac95fc58cb71111