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/app/qt/QtWidgetWrapper.cpp

@@ -0,0 +1,38 @@
+#include "qt/QtWidgetWrapper.h"
+
+#include "gui/GuiElement.h"
+#include "utility/logging/logging.h"
+
+std::shared_ptr<QWidget> QtWidgetWrapper::getWidgetOfElement(std::shared_ptr<GuiElement> element)
+{
+	return getWidgetOfElement(element.get());
+}
+
+std::shared_ptr<QWidget> QtWidgetWrapper::getWidgetOfElement(GuiElement* element)
+{
+	std::shared_ptr<QWidget> widget;
+	std::shared_ptr<QtWidgetWrapper> qtWidgetWrapper = std::dynamic_pointer_cast<QtWidgetWrapper>(element->getWidgetWrapper());
+	if (!qtWidgetWrapper || qtWidgetWrapper.use_count() == 0)
+	{
+		LOG_ERROR("Trying to get the qt widget of non qt gui element.");
+	}
+	else
+	{
+		widget = qtWidgetWrapper->getWidget();
+	}
+	return widget;
+}
+
+QtWidgetWrapper::QtWidgetWrapper(std::shared_ptr<QWidget> widget)
+	: m_widget(widget)
+{
+}
+
+QtWidgetWrapper::~QtWidgetWrapper()
+{
+}
+
+std::shared_ptr<QWidget> QtWidgetWrapper::getWidget()
+{
+	return m_widget;
+}