Resolve order and source subfield issues
Closes #1 (closed), #2 (closed), #3 (closed), kafka-streams-series-transform#7, kafka-streams-series-transform#8, kafka-streams-series-transform#6
Edited by Sebastian Schüpbach
Closes #1 (closed), #2 (closed), #3 (closed), kafka-streams-series-transform#7, kafka-streams-series-transform#8, kafka-streams-series-transform#6