fw.display() function doesn't show all variables of a workflow

[rcelebi]

fw.display() function doesn't show the inputs/outputs of a workflow, shows only the variables between steps.

Example:
@is_fairworkflow(label='My Workflow for converting to Grayscale and adding text')
def my_workflow(im1, text):
"""
A simple addition, subtraction, multiplication workflow
"""
im2 = rgb2gray_image(im1)
im3 = add_text_to_image(im2, text)
return im3