iOS: Tools retain SketchView causing memory leaks

[jeremywiebe]

I was working through a memory leak bug in our React Native app today and I tracked it down to this library. I haven't fully diagnosed the problem, but it looks like there is a circular reference between the tools and the sketch view.

I'm working on fixing this and will be submitting one, or more, PRs to fix this reference cycle.

Here's a view of the leak profiler while running the app. Notice the stair stepping as I navigate into and back out of the view that contains the <SketchView />:

Next I did the same thing and used the Visual Memory Debugger. It showed the retain cycle between the SketchView and various tools.