Merge version 1.7.0

VERSION

arkindex/documents/api/entities.py

arkindex/documents/fixtures/data.json

arkindex/documents/management/commands/build_fixtures.py

arkindex/documents/management/commands/load_export.py

arkindex/documents/managers.py

arkindex/documents/models.py

arkindex/documents/serializers/entities.py

arkindex/documents/serializers/export.py

arkindex/documents/tests/commands/test_cleanup.py

arkindex/documents/tests/commands/test_load_export.py

arkindex/documents/tests/tasks/test_corpus_delete.py

arkindex/documents/tests/tasks/test_export.py

arkindex/documents/tests/tasks/test_worker_results_delete.py

arkindex/documents/tests/test_bulk_classification.py

arkindex/documents/tests/test_bulk_element_transcriptions.py

arkindex/documents/tests/test_bulk_elements.py

arkindex/documents/tests/test_bulk_transcription_entities.py

arkindex/documents/tests/test_bulk_transcriptions.py

arkindex/documents/tests/test_classification.py