Merge branch 'collate' into 'master'

dnadna/__init__.py

dnadna/collate.py

dnadna/datasets.py

dnadna/defaults/training.yml

dnadna/examples/one_event.py

dnadna/nets.py

dnadna/prediction.py

dnadna/schemas/training.yml

dnadna/training.py

dnadna/transforms.py

dnadna/utils/plugins.py

docs/training.rst

tests/test_collate.py

tests/test_datasets.py

tests/test_prediction.py