Merge branch 'mccn_trainer' into 'master'

bob/learn/pytorch/config/mccnn/wmca_mccnn.py

bob/learn/pytorch/datasets/__init__.py

bob/learn/pytorch/datasets/utils.py

bob/learn/pytorch/extractor/image/MCCNN.py

bob/learn/pytorch/extractor/image/__init__.py

bob/learn/pytorch/scripts/train_mccnn.py

bob/learn/pytorch/test/test.py

bob/learn/pytorch/trainers/MCCNNTrainer.py

bob/learn/pytorch/trainers/__init__.py

bob/learn/pytorch/utils.py

doc/guide_mccnn_pad.rst

doc/index.rst

setup.py