C++11 inheritance updates

Add `override` and remove `virtual` where applicable

src/core/PresetPreviewPlayHandle.cpp

@@ -54,7 +54,7 @@ public:
 	{
 	}
 
-	virtual QString nodeName() const
+	QString nodeName() const override
 	{
 		return "previewtrackcontainer";
 	}

src/gui/ControllerConnectionDialog.cpp

@@ -63,7 +63,7 @@ public:
 	}
 
 
-	virtual void processInEvent( const MidiEvent& event, const MidiTime& time, f_cnt_t offset = 0 )
+	void processInEvent( const MidiEvent& event, const MidiTime& time, f_cnt_t offset = 0 ) override
 	{
 		if( event.type() == MidiControlChange &&
 			( m_midiPort.inputChannel() == 0 || m_midiPort.inputChannel() == event.channel() + 1 ) )

src/gui/FxMixerView.cpp

@@ -115,7 +115,7 @@ FxMixerView::FxMixerView() :
 			ChannelArea( QWidget * parent, FxMixerView * mv ) :
 				QScrollArea( parent ), m_mv( mv ) {}
 			~ChannelArea() {}
-			virtual void keyPressEvent( QKeyEvent * e )
+			void keyPressEvent( QKeyEvent * e ) override
 			{
 				m_mv->keyPressEvent( e );
 			}

src/gui/RowTableView.cpp

@@ -39,12 +39,12 @@ public:
 		}
 	virtual void paint( QPainter * painter,
 					const QStyleOptionViewItem & option,
-					const QModelIndex & index ) const;
+					const QModelIndex & index ) const override;
 
 
 protected:
 	virtual void initStyleOption( QStyleOptionViewItem * option,
-					const QModelIndex & index ) const;
+					const QModelIndex & index ) const override;
 
 
 private:

src/gui/widgets/SideBar.cpp

@@ -49,7 +49,7 @@ public:
 		return m_orientation;
 	}
 
-	virtual QSize sizeHint() const
+	QSize sizeHint() const override
 	{
 		QSize s = QToolButton::sizeHint();
 		s.setWidth( s.width() + 8 );
@@ -62,7 +62,7 @@ public:
 
 
 protected:
-	virtual void paintEvent( QPaintEvent * )
+	void paintEvent( QPaintEvent * ) override
 	{
 		QStylePainter p( this );
 		QStyleOptionToolButton opt;