nodeview: improved nodeview usage

Rather than the cumbersome and small "node connectors" (introduced a while ago
when nodes had more than one output), this is a more streamlined system of
connecting nodes (hold Ctrl and drag to connect)

app/widget/nodeview/nodeviewscene.cpp

@@ -213,7 +213,7 @@ void NodeViewScene::ReorganizeInternal(NodeViewItem* src_item, QHash<Node*, int>
     return;
   }
 
-  Node* n = src_item->node();
+  Node* n = src_item->GetNode();
 
   QList<Node*> connected_nodes = n->GetImmediateDependencies();