ui: implemented gui abstraction and dummy view

- added abstract class tree for gui elements.
- implemented concrete gui classes that wrap the qt specific content.
- implemented first DummyView which plays nice with the ViewManager.

review id = 12

src/lib/component/view/View.h

@@ -1,11 +1,29 @@
 #ifndef VIEW_H
 #define VIEW_H
 
+#include <memory>
+
+#include "utility/math/Vector2.h"
+
+class GuiElement;
+class ViewManager;
+
 class View
 {
 public:
+	View(std::shared_ptr<ViewManager> viewManager, std::shared_ptr<GuiElement> rootElement, const Vec2i& minSize);
 	virtual ~View();
+
+	std::shared_ptr<GuiElement> getRootElement();
+
+	int getMinWidth() const;
+	int getMinHeight() const;
+	Vec2i getMinSize() const;
+
+private:
+	std::shared_ptr<ViewManager> m_viewManager;
+	std::shared_ptr<GuiElement> m_rootElement;
+	Vec2i m_minSize;
 };
 
-
 #endif // VIEW_H