Implement format command

README.md

dan/datasets/__init__.py

dan/datasets/format/__init__.py

dan/datasets/format/atr.py

dan/datasets/format/bessin.py

dan/datasets/format/generic.py

dan/datasets/format/simara.py

dan/datasets/format/synist.py

dan/manager/dataset.py

dan/manager/metrics.py

dan/manager/ocr.py

dan/manager/training.py

dan/manager/utils.py

dan/ocr/document/train.py

dan/ocr/line/generate_synthetic.py

dan/ocr/line/train.py

dan/post_processing.py

dan/utils.py

requirements.txt