some J3D/misc cleanup (#2628)

* some j3d cleanup

* begin using uintptr_t

* j3dgraphbase cleanup

* j3dgraphanimator cleanup

src/d/actor/d_a_obj_katatsumuri.cpp

@@ -840,7 +840,7 @@ int daObjKAT_c::create() {
                   fopAcM_GetSpeed_p(this), NULL, NULL);
 
         J3DModel* model = mpMorfSO->getModel();
-        model->setUserArea((u32)this);
+        model->setUserArea((uintptr_t)this);
 
         for (u16 i = 0; i < model->getModelData()->getJointNum(); i++) {
             if (i != 0) {