Fixing body position of heightmap object

Due to the nature of heighfield creation in cannon.js, the heightmap's
position is not the center of the bounding box. Bounding box should be
completely ignored

src/Physics/Plugins/babylon.cannonJSPlugin.js

@@ -197,10 +197,9 @@ var BABYLON;
             }
             //If it is a heightfield, if should be centered.
             if (shape.type === CANNON.Shape.types.HEIGHTFIELD) {
-                body.position = body.position.vadd(new CANNON.Vec3(-shape.dim, 0, shape.dim));
+                body.position = new CANNON.Vec3(-shape.dim, 0, shape.dim).vadd(mesh.position);
                 //add it inverted to the delta 
-                deltaPosition.x += shape.dim;
-                deltaPosition.z -= shape.dim;
+                deltaPosition = mesh.position.add(new BABYLON.Vector3(shape.dim, 0, -shape.dim));
             }
             //add the shape
             body.addShape(shape);

src/Physics/Plugins/babylon.cannonJSPlugin.ts

@@ -235,10 +235,9 @@
             
             //If it is a heightfield, if should be centered.
             if (shape.type === CANNON.Shape.types.HEIGHTFIELD) {
-                body.position = body.position.vadd(new CANNON.Vec3(-shape.dim, 0, shape.dim));
+                body.position = new CANNON.Vec3(-shape.dim, 0, shape.dim).vadd(mesh.position);
                 //add it inverted to the delta 
-                deltaPosition.x += shape.dim;
-                deltaPosition.z -= shape.dim;
+                deltaPosition = mesh.position.add(new BABYLON.Vector3(shape.dim, 0, -shape.dim));
             }
             
             //add the shape