1. I fixed a bug in the collection of force data. When I did the boxhydrodynamics test I noticed that the gravity force acting on a body was not being reported by bullet. I dug a little deeper and gravity is not applied until the step sim method, and it is getting cleared out before we step out of that method. I had to hook up the setInternalTickCallback and collect the forces then. This meant that I needed to split this data collection into its own method within the simulator. So I added the AfterStepSimulation method for this.

2. Got the hydro tests working. However, There is an odd discrepancy in the way the fluid drag is working in vortex and bullet. I believe the code I wrote in bullet is correct. The vortex code is limiting drag to never be any larger than the gravity force. Not sure why they are doing this because it seems incorrect to me. There is not anything I can really do about the vortex code, so for the moment I will let it be.