Ported to 0.9.0

Months ago I found this repo, in an old (really old) thread in the forums, I found it really interesting, but I couldn't run the test because they were made for 0.8.0, I thought about porting it to 0.9.X thinking it would be hard, but it wasn't hard at all, minor fixes were needed.

I think this project is really good to see how different physics simulation behave. Nice work!

PS: Maybe Box2D physics would be nice (just to compare) but not sure how that could be done.