message: Query selector not needed. This allows users to pass a node instead of a string as the element.
diff: @@ -116,7 +116,7 @@ function embed(el, spec, opt, callback) {
  try {
  var view = new vega.View(runtime)
  .logLevel(vega.Warn)
  - .initialize(document.querySelector(el))
  + .initialize(el)
  .renderer(renderer)
  .hover()
  .run();
  