How to clean bevy up after app run ?

[fantasyRqg]

I managed to run bevy with android surfaceview and enable to reenter bevy with the same surfaceview.

But after serveral tests I noticed that bevy doesn't release all the resources it allocated.
Like, Resource asset, I store some Image handle in it. After serveral runs, the graphic memory usage keep increasing.

And I also find std::mem::forget used in some cases which I think is impossible to release.