SpinSlider and ScrollSpinBox read-only support

PIVariantEdit - support for read-only for all types
PIValueTreeEdit - drop Parent grouping, default now Groups, full grouping control, global read-only support, fix new label error

libs/widgets/scroll_spin_box.h

@@ -49,6 +49,9 @@ public:
 	int minimum() const { return m_minimum; }
 	int maximum() const { return m_maximum; }
 
+	void setReadOnly(bool r);
+	bool isReadOnly() const { return m_read_only; }
+
 protected:
 	void changeEvent(QEvent * e);
 	void resizeEvent(QResizeEvent * e);
@@ -62,7 +65,7 @@ protected:
 	QString last_text;
 	double last_value, scroll_scale, sensivity_;
 	double m_minimum, m_maximum;
-	bool canceled;
+	bool canceled, m_read_only = false;
 
 public slots:
 	void setSensivity(double s) { sensivity_ = s; }