[GCAD] Added basic action system.
[GCAD] Added OBBSpatialQueryable3d.
[GCAD] Rewrote EngineEntitiesSpatialQueryable to use OBBSpatialQueryable3d.
[GCAD] Renamed EngineEntitiesSpatialQueryable to NativeEntityList.
[GCAD] Rewrote PACPartsSpatialQueryable to use OBBSpatialQueryable3d.
[GCAD] Renamed PACPartsSpatialQueryable to PACPartList.
[GCAD] Added EventedCollectionCuller.
[GCAD] Removed objects are now auto-removed from the context menu selection.