Scene Editor: Presenting the supercharged Scene Struct. Refactored main parts that add/remove/reparent stuff so that everything can be batched. Ran an 5000 entity import with Scene Struct open in about few seconds and not losing responsivenes (about 200msec of blocking calls in total). Before Tundra would have not recovered from this due to adding one-by-one items which in turn sorted the whole tree for each item and subitem (ents under groups or comps under ents). Rewrote Acking to not remove old id items and recreting them (one of main bottle necks once server responded with acked ids).