Fix bug whereby AABBs were reused from previous items due to use of a pool, resulting in missed collisions.
Also use full mask collision checks for all cases except generic update.
Change render BVH update scheme from once per update_dirty_instances to a new update_scenarios function called once per draw.
Fix lights not being properly unpaired.
Fixed bug in add_changed_item where AABBs were not being updated due to more than one update per tick.
Complete rewrite of spatial partitioning using a bounding volume hierarchy rather than octree.
Switchable in project settings between using octree or BVH for rendering and physics.
