some J3D/misc cleanup (#2628)

* some j3d cleanup

* begin using uintptr_t

* j3dgraphbase cleanup

* j3dgraphanimator cleanup

src/d/actor/d_a_ni.cpp

@@ -2086,7 +2086,7 @@ static BOOL useHeapInit(fopAc_ac_c* i_this) {
 
     J3DModel* model = a_this->mpMorf->getModel();
     a_this->model = model;
-    model->setUserArea((u32)a_this);
+    model->setUserArea((uintptr_t)a_this);
 
     for (u16 i = 0; i < model->getModelData()->getJointNum(); i++) {
         model->getModelData()->getJointNodePointer(i)->setCallBack(nodeCallBack);