Instance scene and node getters, so we minimize instance memory
Notes
[BROKEN] First step of instance-event refactoring (4 stitching/layering tests failing, sims won't start)
More assertions for better tracking
Adding log lines for layer notifications
Adding full tree tracking for instances
A few fixes and added assertions
A few more fixes
Fixing affectedLayers issue
Adding subtree paint dirty flag and notifier, fixes dirty region issue
Reindexing fix
Adding debugging reference
Merging with instances