[Bug] The option plot_dependency_graph is incompatible to batched(), split_future() and get_item_from_future()

[jan-janssen]

The advanced graph manipulation techniques cannot be visualized using the plot_dependency_graph graph option. This includes:

• batched() - for resolving run time dependencies
• split_future() - for splitting a future object which results in a tuple into multiple future objects
• get_item_from_future() - for selecting a specific key of a future object which results in a dictionary

[jan-janssen]

I tested a first implementation for the later two in #820