We should modify the code in dffml/cli/dataflow.py within the Diagram class to not show operation.inputs which have default values. It makes for giant diagrams sometimes. We should provide an option to show them again

I've selected Ggnn.init(vocabulary,node_y_dimensionality,graph_y_dimensionality,graph_x_dimensionality,use_selector_embeddings,test_only,name) for refactoring, which is a unit of 72 lines of code and 7 parameters. Addressing this will make our codebase mo