message: demo: Add packVertex to dev runs
  This lets us compare mesh compression to raw deflate.
diff: @@ -636,6 +636,7 @@ void processDev(const char* path)
  meshopt_optimizeVertexFetch(&copy.vertices[0], &copy.indices[0], copy.indices.size(), &copy.vertices[0], copy.vertices.size(), sizeof(Vertex));
  encodeIndex(copy);
  + packVertex(copy);
  encodeVertex(copy);
  encodeVertexPred(copy);
  }
  