data: saving typedef to Storage

This change save typedef expressions to the Storage using a node of type Node::NODE_TYPEDEF and an edge of type
Edge::EDGE_TYPEDEF_OF that leads to the original type, with the qualifiers saved as DataType on the edge.

src/lib/data/graph/Node.h

@@ -22,7 +22,8 @@ public:
 		NODE_FUNCTION,
 		NODE_METHOD,
 		NODE_NAMESPACE,
-		NODE_ENUM
+		NODE_ENUM,
+		NODE_TYPEDEF
 	};
 
 	Node(NodeType type, const std::string& name);