ui: redesigned graph overview and use new list layouting within overview bundles

* overview bundles imitate style of bundled node type
* removed bundle for built-in types
* show contents of overview bundle in vertical list layouted with new ListLayouter
* nodes starting with the same letter are grouped with the letter displayed above
* pressing the letter key will scroll to the group
* also use this list layouting for namespace & package contents
* renamed BucketGrid to BucketLayouter
* moved used functions of GraphPostProcessor to GraphViewStyle and removed GraphPostProcessor

fortune cookie message = Don't be afraid to take that big step

src/lib_gui/qt/view/graphElements/QtGraphNodeText.cpp

@@ -0,0 +1,20 @@
+#include "qt/view/graphElements/QtGraphNodeText.h"
+
+QtGraphNodeText::QtGraphNodeText(const std::string& name)
+{
+	setName(name);
+}
+
+QtGraphNodeText::~QtGraphNodeText()
+{
+}
+
+bool QtGraphNodeText::isTextNode() const
+{
+	return true;
+}
+
+void QtGraphNodeText::updateStyle()
+{
+	setStyle(GraphViewStyle::getStyleOfTextNode());
+}