Support the Yield Events

[azettl]

It would be great if the next version of the python lib. could support the yield events.

[davidattwater]

I believe that the library does support YieldFloor events. You need to define the handler self.on_yield_floor if you want your agent to respond to the event. To add this event to an envelope use:

envelope.events.append(YieldFloorEvent(reason="my reason"))

Have I misunderstood the purpose of this issue?