ui: bundling nodes in the graph view

This change bundles similar nodes in the graph view together. When the bundled node or it's aggregation edge are clicked,
then the bundle is split. This change also adds an arrow to the aggregation edge based on the direction of it's edges.

bin/app/data/src/sample/samples.cpp

@@ -121,3 +121,41 @@ public:
 
 Basket<Apple> apples;
 Basket<Pear> pears;
+
+
+class Dog {};
+
+class Cat
+{
+	Dog getDog();
+};
+
+class Bird
+{
+	Dog getDog();
+	Cat getCat();
+};
+
+class Fish
+{
+	Dog getDog();
+	Cat getCat();
+	Bird getBird();
+};
+
+class Horse
+	: public Dog
+{
+	Dog getDog();
+	Cat getCat();
+	Bird getBird();
+	Fish getFish();
+};
+
+
+class Building {};
+class House : public Building {};
+class Tower : public Building {};
+class SkyScrapper : public Building {};
+class Mansion : public Building {};
+class Shard : public House, public Tower, public SkyScrapper, public Mansion {};