Use Fyne animation API instead of goroutine to run simulation

[dweymouth]

Switch to using fyne.NewAnimation to drive the evolution of the game. This means it will be automatically thread-safe under the upcoming threading model changes and also serves as an example of fyne.NewAnimation

[andydotxyz]

Hmm, I see how this will be beneficial in the future from a threading point of view - but I'm not sure it's a great demo of the animation API, as it doesn't actually use the animation progress to drive any graphics update...

[dweymouth]

Maybe we will need a new API like fyne.NewTicker once the new threading is in place, for things that should run on every frame but don't need the whole animation framework?

[andydotxyz]

Maybe we will need a new API like fyne.NewTicker once the new threading is in place, for things that should run on every frame but don't need the whole animation framework?

Maybe. Maybe also the infinite animation you suggested would not pass in the parameter that we are ignoring here as you can't tell how close to the end it is...?