Added initial abstract class rendering

tests/t00002/t00002.cc

@@ -5,16 +5,35 @@ namespace t00002 {
 
 class A {
 public:
-    virtual void foo() {}
+    virtual void foo_a() = 0;
+    virtual void foo_c() = 0;
 };
 
 class B : public A {
+public:
+    virtual void foo_a() override {}
 };
 
 class C : public A {
+public:
+    virtual void foo_c() override {}
 };
 
 class D : public B, public C {
+public:
+    void foo_a() override
+    {
+        for (auto a : as)
+            a->foo_a();
+    }
+
+    void foo_c() override
+    {
+        for (auto a : as)
+            a->foo_c();
+    }
+
+private:
     std::vector<A *> as;
 };
 }