more robust fetching framework for long running generations that is resilient to the user backgrounding the app or somehow queuing up multiple generations (like an internal database of the queue)

[amiantos]

Partial fix for this last night, using timers and runloops to keep backgrounding and user interactivity from messing with the timers.

[amiantos]

I rewrote everything into a separate module (basically a view model) to handle generations and it seems pretty resilient at the moment to getting paused in the background, but will still lose a generation if the app is fully killed. I think that's okay enough for 1.0.