Support ordering in ElementPath + add_parent

arkindex/documents/cache.py

arkindex/documents/migrations/0016_auto_20180704_1103.py

arkindex/documents/migrations/0017_auto_20180704_1513.py

arkindex/documents/models.py

arkindex/documents/tests/test_transcription_create.py

arkindex/project/fields.py

arkindex/project/runtests.py

arkindex/project/tests/__init__.py

arkindex/project/tests/test_fields.py

arkindex/project/tests/test_polygon.py

arkindex/project/tests/test_polygonfield.py

arkindex/project/tests/test_tools.py