Missing forwarding for constructor args

[adcgx]

In areas like:

template <class NodeType, typename... Args>
SomeBuilder<Parent> leaf(Args... args)
{
    auto child = std::make_shared<NodeType>((args)...);
    node->setChild(child);
    return *this;
}

there needs to be forwarding to avoid unintended copying:

template <class NodeType, typename... Args>
SomeBuilder<Parent> leaf(Args&&... args)
{
    auto child = std::make_shared<NodeType>(std::forward<Args>(args)...);
    node->setChild(child);
    return *this;
}