Work on plugin mechanism

Context actions have become normal actions in the pluginwidget so the widget knows abot them and
can easily do things like enable/disable.

pglab/plugin_support/LMainMenu.h

@@ -0,0 +1,56 @@
+#ifndef LMAINMENU_H
+#define LMAINMENU_H
+
+#include <QString>
+#include <vector>
+
+class QAction;
+
+class LMenuGroupItem {
+public:
+	LMenuGroupItem(QAction *action, int position)
+		: m_menuAction(action)
+		, m_position(position)
+	{}
+
+	int position() const { return m_position; }
+
+private:
+	QAction *m_menuAction;
+	int m_position;
+};
+
+// Menu's are divided into logical groups,
+// these groups form only a single level they are NOT submenu's
+class LMenuGroup {
+public:
+
+	explicit LMenuGroup(QString group_id);
+	QString groupId() const;
+
+private:
+	QString m_groupId;
+};
+
+class LMenu {
+public:
+	QString menuId() const;
+
+	void addGroup(const LMenuGroup &group)
+	{
+		m_groups.push_back(group);
+	}
+private:
+	using Groups = std::vector<LMenuGroup>;
+
+	QString m_caption;
+	Groups m_groups;
+};
+
+
+class LMainMenu: public LMenu {
+public:
+	LMainMenu();
+};
+
+#endif // LMAINMENU_H