input bug in composit option

[YipengHu]

2. In addition there is an issue with the 'composite' option (both global and local transforms), which throws the following error:

Traceback (most recent call last):
  File "label-reg/training.py", line 35, in <module>
    image_fixed=input_fixed_image)
  File "~/label-reg/labelreg/networks.py", line 13, in build_network
    return CompositeNet(**kwargs)
  File "~/label-reg/labelreg/networks.py", line 89, in __init__
    image_moving=global_net.warp_image(),
TypeError: warp_image() missing 1 required positional argument: 'input_'