Train wont leave until fully loaded#1979

Please make a rule or option so that trains or wagons wont leave a loader until a shape or paint is actually loaded into the wagon.

imo best way would be a dropdown for the train stop:

1. current behavior
2. only leave when full
3. bypass train stop if nothing can picked up or dropped off

1. Train sits there forever if you forget or do not need an input. Then you will really complain.
2. Current behavior adds about 2 seconds to a trip, you’ll be fine.

Coming with 0.1.0