FIX: mostly arguments and return values

integrationtests/basic_example/test_basic.py

integrationtests/test_issues.py

integrationtests/test_realworld_example.py

src/caoscrawler/__init__.py

src/caoscrawler/crawl.py

src/caoscrawler/scanner.py

src/caoscrawler/version.py

unittests/test_cfood_metadata.py

unittests/test_converters.py

unittests/test_issues.py

unittests/test_json.py

unittests/test_macros.py

unittests/test_scalars_cfood.py

unittests/test_table_converter.py

unittests/test_tool.py

unittests/test_tool_extended.py

unittests/test_variable_substitutions.py