prevent ball falling through world by reparenting to player

#165 was rejected because parenting the ball to world doesn't jive with our multiplayer focus.
So this one has the same fix only now the ball is parented to player. This does resolve the issue of the ball falling through the world mentioned in the discussion of #22

I changed the parent in the player of level_full, and in the single_View player of level_full_local_multi, and in both players of twoSplit_View of level_full_local_multi

I was able to test only the single_View of level_full_local_multi because level_full appears not to load anymore.

(PS: prefabs would have helped here)