Introduce QML-based welcome screen using desktop components

Implements new XML-based format for examples, demos & tutorials

Done-with: Primrose Mbanefo <ext-primrose.mbanefo@nokia.com>
Change-Id: I42c0afdb419cffe5637cd4f298e828d09e0fb15a
Reviewed-on: http://codereview.qt.nokia.com/840
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/plugins/coreplugin/modemanager.h

@@ -70,6 +70,7 @@ public:
     void addWidget(QWidget *widget);
 
     void activateModeType(const QString &type);
+    void setModeBarHidden(bool hidden);
 
 signals:
     void currentModeAboutToChange(Core::IMode *mode);