message: Observer now can directly accept DOM Node
diff: @@ -24,7 +24,16 @@ export class Observer
  static observe(selector, callback, options)
  {
  callback([]);
  - return [...document.querySelectorAll(selector)].map(
  + let elements = selector;
  + if (typeof selector === "string")
  + {
  + elements = [...document.querySelectorAll(selector)];
  + }
  + else if (!Array.isArray(selector))
  + {
  + elements = [selector];
  + }
  + return elements.map(
  it =>
  {
  const observer = new Observer(it, callback);
  