singleFrameDriver is only running with a single process

Python 3 super docs are at https://docs.python.org/3/library/functions.html?highlight=super#super which then tells you to read https://rhettinger.wordpress.com/2011/05/26/super-considered-super/

To be honest, while I do remember being unhappy with super in the past, I don't remember the arguments for and against anymore, and I don't think that unease extended to diamond inheritance when all classes have a nontrivial constructors; I think super is till the only way to handle that situation correctly.

I wonder what the situation is in Python 3 (or futurized Python 2), where I hear super is better - @Tim Jenness?

Thanks, I'll go ahead and merge now.

I'm not sure how this is any more fragile than usual, nor how super would fix it (using super in a class hierarchy that doesn't all use super is dangerous, and I thought you were against using it for that reason); perhaps you could explain that offline for me?

Merged to master.

I don't disagree with your analysis that the current code is safe, but I still worry that it's fragile w.r.t. the addition of new subclasses. That said, TaskRunner is perhaps not long for this world with SuperTask on the horizon, so it's probably not necessary to fix this now.