removed two cached optimizations, type in btTransform and cached inverse transform (todo: test performance impact)
committed fixes that make the code adhere to 'who creates it, also destroys it'
removed deletion of motionstate in CcdPhysics/CcdPhysicsController destructor
disabled m_type optimization in SimdTransform (making the memory size 64 byte, potentially more cache friendly)
fixed a bug in island generation, causing the activation not propagating in one frame, but one 'layer' of rigidbodies at a time