build: fix compiler and cmake warnings

added missing virtual destructor
fixed a warning in token.h: expression with side effects will be evaluated despite being used as an operand to 'typeid'
CMP00043 Cmake warning
added missing override keyword

src/app/qt/element/QtProjectSetupScreen.h

@@ -31,7 +31,7 @@ Q_OBJECT
 public:
 	QtProjectSetupScreen(QWidget* parent = 0);
 	QSize sizeHint() const Q_DECL_OVERRIDE;
-	virtual void setup();
+	virtual void setup() override;
 private slots:
 	void handleCreateButtonPress();
 	void handleCancelButtonPress();

src/app/qt/element/QtSettingsWindow.h

@@ -16,8 +16,8 @@ public:
 protected:
 	QWidget* m_window;
 
-	void keyPressEvent(QKeyEvent* event);
-	void resizeEvent(QResizeEvent* event);
+	void keyPressEvent(QKeyEvent* event) Q_DECL_OVERRIDE;
+	void resizeEvent(QResizeEvent* event) Q_DECL_OVERRIDE;
 	void mouseMoveEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
 	void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
 	void mouseReleaseEvent(QMouseEvent *event) Q_DECL_OVERRIDE;

src/app/qt/element/QtStartScreen.h

@@ -22,7 +22,7 @@ class QtStartScreen : public QtSettingsWindow
 public:
 	QtStartScreen(QWidget* parent = 0);
 	QSize sizeHint() const Q_DECL_OVERRIDE;
-	virtual void setup();
+	virtual void setup() override;
 
 signals:
 	void openOpenProjectDialog();

src/app/qt/view/QtGraphViewStyleImpl.cpp

@@ -2,6 +2,10 @@
 
 #include <QFontMetrics>
 
+QtGraphViewStyleImpl::~QtGraphViewStyleImpl()
+{
+}
+
 float QtGraphViewStyleImpl::getCharWidthForNodeType(Node::NodeType type)
 {
 	return QFontMetrics(QtGraphNode::getFontForNodeType(type)).width("QtGraphNode::QtGraphNode::QtGraphNode") / 37.0f;

src/app/qt/view/QtGraphViewStyleImpl.h

@@ -8,6 +8,7 @@ class QtGraphViewStyleImpl
 	: public GraphViewStyleImpl
 {
 public:
+	virtual ~QtGraphViewStyleImpl();
 	virtual float getCharWidthForNodeType(Node::NodeType type);
 	virtual float getCharHeightForNodeType(Node::NodeType type);
 };