Documentation of Babylon3 and physics

[Dwengo]

I've been looking at implementing physics into a simple scene, but I feel the documentation is out of date and thus much of the stuff you find online is out of date also. Take for example meshes, in order to activate physics on one, you now need to set the `mesh.physicsImposter` member variable, whereas almost all relevant topics call the (now redundant) function `myMesh.setPhysicsState()`.

This is confounded by the fact that oimojs has documentation that fleets between Three, Babylon, and sometimes neither!

Could we perhaps update the Babylon playground to contain more physics demos using Babylon 3 at the very minimum?

Is anyone else finding the out of date content available online an issue? could we do something more in the documentation?

[GameMonetize]

What about this one:

http://doc.babylonjs.com/overviews/using_the_physics_engine