IntToFloatTensor in the MaskBlock?

Hi there,

I noticed that the MaskBlock also contains an IntToFloatTensor batch transformation and I wonder why it is there. Batch transforms are not applied to label masks if you build a U-Net learner with fastai (after all you want the masks as int tensors). Is this a bug or am I missing something?

def MaskBlock(codes=None):
    "A `TransformBlock` for segmentation masks, potentially with `codes`"
    return TransformBlock(type_tfms=PILMask.create, item_tfms=AddMaskCodes(codes=codes), **batch_tfms=IntToFloatTensor**)