ConveyorBusBuilder

I think we can close this with the documentation we have currently in the reference now at time of writing

@bluenote10 I've tested the order twice on different machines with different sound systems and OS's and for both, the channel order is LRLRL... I suspect that this is ultimately dependent...

I think there should definitely be the keywords on their own at least to start just to get it out there (I'm worried that it may turn into another reference...

OK funny enough with a comment from ehuss on a different issue, I learned a thing that I should have known long before: keywords are documented in the std docs....