Option format inconsistent re: hyphens/underscores

[boyleconnor]

Some of the options in the graph model scripts are of the format --with-hyphens and some are of the format --with_underscores.

E.g.:

• adam/adam_preprocessing/shape_stroke_graph_learner.py

  Line 42 in a43a362

  "--num_train_steps",

• adam/adam_preprocessing/shape_stroke_graph_inference.py

  Line 68 in a43a362

  "--dir-num",

It should be consistent, and my inclination is that it should by --with-hyphens.

[lichtefeld]

I agree with the hyphens preference.