COMP: Fix warnings about override on public destructors (#788)

src/AutoHideTab.h

@@ -93,7 +93,7 @@ public:
 	/**
 	 * Virtual Destructor
 	 */
-	virtual ~CAutoHideTab();
+    ~CAutoHideTab() override;
 
 	/**
 	 * Update stylesheet style if a property changes

src/DockAreaWidget.h

@@ -199,7 +199,7 @@ public:
 	/**
 	 * Virtual Destructor
 	 */
-	virtual ~CDockAreaWidget();
+	~CDockAreaWidget() override;
 
 	/**
 	 * Returns the dock manager object this dock area belongs to

src/DockContainerWidget.h

@@ -219,7 +219,7 @@ public:
 	/**
 	 * Virtual Destructor
 	 */
-	virtual ~CDockContainerWidget();
+    ~CDockContainerWidget() override;
 
 	/**
 	 * Adds dockwidget into the given area.

src/DockWidget.h

@@ -289,7 +289,7 @@ public:
     /**
      * Virtual Destructor
      */
-    virtual ~CDockWidget();
+    ~CDockWidget() override;
 
     /**
      * We return a fixed minimum size hint or the size hint of the content

src/FloatingDockContainer.h

@@ -220,7 +220,7 @@ public:
 	/**
 	 * Virtual Destructor
 	 */
-	virtual ~CFloatingDockContainer();
+	~CFloatingDockContainer() override;
 
 	/**
 	 * Access function for the internal dock container