onLeaveScene callback/event

[dbarnett]

Would it be okay to have a hook that gets called on leaving a scene? There are some kinds of cleanup like stopping music or conditionally destroying objects with stay() that get messy trying to do ad-hoc cleanup before any code leaves the scene.

I could imagine this offered either via another SceneOpts arg to the scene() function or as an onLeaveScene(id, action) event helper.

[lajbel]

Very good idea! Up Voted

[slmjkdbtl]

Added in f80392b