Added list of constraints to the tables page.

Last column shows the full textual definition until I have decided on
a better way to visualize the details.

pglab/IconColumnDelegate.h

@@ -0,0 +1,29 @@
+#ifndef ICONCOLUMNDELEGATE_H
+#define ICONCOLUMNDELEGATE_H
+
+#include <QStyledItemDelegate>
+#include <map>
+
+/** This class asumes that the string values supplies for the column data
+ * can be Resolved by QIcon to an actual icon. Icons are cached and reused.
+ *
+ */
+class IconColumnDelegate: public QStyledItemDelegate {
+public:
+	IconColumnDelegate(QWidget *parent = nullptr);
+	~IconColumnDelegate();
+
+	void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
+	QSize sizeHint(const QStyleOptionViewItem &option,
+					   const QModelIndex &index) const override;
+
+	void clearCache();
+private:
+	using t_IconCache = std::map<QString, QIcon*>;
+
+	mutable t_IconCache m_Icons;
+
+	QIcon* getIcon(const QString &name) const;
+};
+
+#endif // ICONCOLUMNDELEGATE_H