Memory leak

Nobody has claimed this yet.

I am encountering a persistent memory allocation issue with this otherwise awesome library.

Specifically, when a UIPopoverPresentationController (showing a modal VC with extended data on a given node, in response to user interaction) is presented and dismissed repeatedly, the app crashes with a [Render] CoreAnimation: failed to allocate IOSurface error.

This appears to be an issue related to the handling of nodes on calling the session.pause() method from the AR VC's viewDidDisappear code. I suspect this problem is related to the the issue discussed here:
https://stackoverflow.com/questions/28738551/how-can-i-remove-all-nodes-from-a-scenekit-scene

It looks like the annotationManager class here is not fully deallocating resources when the session is paused (nor on on calling removeAllAnnotations). Unfortunately I haven't been able to resolve this based on the SO answer.

Start by tracing annotationManager's handling of nodes during session.pause() from the AR view controller's viewDidDisappear and during removeAllAnnotations. Reproduce repeated UIPopoverPresentationController presentation and dismissal, then verify that resources are released and the repeated flow no longer reaches the CoreAnimation IOSurface allocation failure.

Written by the indexing model from the issue text.