Refactor WorldObject and Physics

Extracted from the ParticlePhysics PR, issues #179 and #237 

* remove bulletphysics, add parameters to normal physics

* remove protected bad worldobject constructor, add initialize
* remove worldobject constructor with worldtransform
* remove center from worldobject constructor (tests?)

* add Normandy, Wall and Planet to the HUD again
* remove testClusterMovable