BulletSim: parameterize C# HACD hull creation. Add feature of reducing max hull count for simple (non-cut prims) meshes.
BulletSim: fix possible race condition where an prim's asset can be requested quicker than the asset fetcher returns and thus falsely reporting that an asset was not fetched and defaulting the assset to a bounding box.
BulletSim: small tweaks and formatting in the parameter fetching code.
BulletSim: new algorithm for vertical attraction which uses quaternion
arithmetic to compute the shortest path between the current tilt
and vertical.