can we use asyncio.task for thermocycling runs?

currently we just return directly

can we use tasks?

the protocol will have to be awaited at some point, but in a notebook context it can just run in the background

that seems to be a nicer api (you can choose when to wait for it to finish) rather than 

it will also allow us to run some cleanup (eg resetting curent profile / machine busy status) after a run