Update for file header, docstrings, and PEP8/PEP257

tests/__init__.py

tests/common.py

tests/components/automation/test_init.py

tests/components/automation/test_numeric_state.py

tests/components/automation/test_state.py

tests/components/automation/test_template.py

tests/components/automation/test_zone.py

tests/components/binary_sensor/test_command_sensor.py

tests/components/device_tracker/test_init.py

tests/components/device_tracker/test_locative.py

tests/components/device_tracker/test_mqtt.py

tests/components/device_tracker/test_owntracks.py

tests/components/garage_door/test_demo.py

tests/components/light/test_init.py

tests/components/light/test_mqtt.py

tests/components/media_player/test_demo.py

tests/components/notify/test_demo.py

tests/components/rollershutter/test_mqtt.py

tests/components/sensor/test_command_sensor.py

tests/components/sensor/test_mfi.py